CircRNA: a novel type of biomarker for cancer. Breast Cancer. 2018;25:1-7. [PMID: 28721656 DOI: 10.1007/s12282-017-0793-9]

The role of polypeptides encoded by ncRNAs in cancer

It was previously thought that ncRNA could not encode polypeptides, but recent reports have challenged this notion. As research into ncRNA progresses, it is increasingly clear that it serves roles beyond traditional mechanisms, playing significant regulatory roles in various diseases, notably cancer, which is responsible for 70% of human deaths. Numerous studies have highlighted the diverse regulatory mechanisms of ncRNA that are pivotal in cancer initiation and progression. The role of ncRNA-encoded polypeptides in cancer regulation has gained prominence. This article explores the newly identified regulatory functions of these polypeptides in three types of ncRNA-lncRNA, pri-miRNA, and circRNA. These polypeptides can interact with proteins, influence signaling pathways, enhance miRNA stability, and regulate cancer progression, malignancy, resistance, and other clinical challenges. Furthermore, we discuss the evolutionary significance of these polypeptides in the transition from RNA to protein, examining their emergence and conservation throughout evolution.

T cell-related circRNA pairs to predict prognosis of patients with esophageal squamous cell carcinoma

The prognosis for esophageal squamous cell carcinoma (ESCC), a prevalent and aggressive form of cancer, remains poor despite advancements in treatment options. Addressing the gap in comprehensive prognostic information derived from circRNA expression profiles for ESCC, our study aimed to establish a linkage between circRNA expressions and ESCC prognosis. To achieve this, we first developed an optimized prognostic model named T cell-related risk score (TRRS), which integrates T cell-associated features with machine learning algorithms. In parallel, we re-analyzed existing RNA-seq datasets to redefine the expression profiles of circRNAs and mRNAs. Utilizing the TRRS as a foundational "bridge," we identified circRNAs correlated with TRRS, leading to the development of a novel circRNA pair-based prognostic model, the TCRS, which is independent of specific expression levels. Further investigations uncovered two circRNAs, circNLK(5,6,7).1 and circRC3H1(2).1, with potential functional significance. These findings underscore the utility of these risk scores as tools for predicting overall survival and identifying potential therapeutic targets for ESCC patients.

Circ_0023990 Promotes the Proliferation, Invasion, and Glycolysis of Esophageal Squamous Cell Carcinoma Cells Via Targeting miR-6884-5p/PAK1 Axis

Circular RNAs are emerging players in human cancers, including esophageal squamous cell carcinoma (ESCC). Herein, we assessed the expression level of circ_0023990 and explored the molecular mechanisms of circ_0023990 in ESCC. circ_0023990, miR-6884-5p, and PAK1 expressions in ESCC tissues and cells were detected by quantitative real-time polymerase chain reaction and western blot. ESCC cells were transfected with different constructs to alter the expression of circ_0023990, miR-6884-5p, and PAK1. The effect of circ_0023990 on the proliferation, invasion, and glycolysis of ESCC cells was observed. The interaction between circ_0023990 and miR-6884-5p and between miR-6884-5p and PAK1 were explored. A mouse model of ESCC was established to study the in vivo effect of circ_0023990 knockdown on tumor formation.The expression levels of circ_0023990 was upregulated in ESCC tissues and cells. Inhibiting circ_0023990 suppressed the proliferation, invasion, and glycolysis of ESCC cells. circ_0023990 might target miR-6884-5p and consequently modulate the expression and activity of PAK1. Knockdown of circ_0023990 led to significantly reduced tumor volume and weight in mice with ESCC.These findings overall suggest an oncogenic role of circ_0023990 in ESCC. Future research is warranted to confirm the expression pattern and clinical significance of circ_0023990 in ESCC.

CircSFMBT2 Plays an Oncogenic Role in Lung Adenocarcinoma Depending on the miR-1305/SALL4 Axis

Circular RNAs (circRNAs) exhibit significant functions in diverse malignant tumors, including lung adenocarcinoma (LUAD). In this study, we aimed to elucidate the role of circRNA scm like with four mbt domains 2 (circSFMBT2) in LUAD. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot assay or immunohistochemistry (IHC) assay was performed for quantification of circSFMBT2, microRNA-1305 (miR-1305), spalt like transcription factor 4 (SALL4), proliferating Cell Nuclear Antigen (PCNA) or Ki-67. 5-ethynyl-2'-deoxyuridine (EdU) assay, transwell assay and flow cytometry analysis were applied to analyze cell proliferation, metastasis and apoptosis, respectively. Mouse xenograft model was established to explore the function of circSFMBT2. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to estimate the relationship between miR-1305 and circSFMBT2 or SALL4. CircSFMBT2 was upregulated in LUAD and related to advanced TNM stage and poor prognosis. CircSFMBT2 knockdown suppressed cell proliferation, metastasis, glycolysis and induced apoptosis in LUAD cells in vitro as well as tumor formation in vivo. CircSFMBT2 directly targeted miR-1305, and miR-1305 inhibition reversed circSFMBT2 knockdown-mediated inhibitory effects on LUAD malignant behaviors. SALL4 was the target gene of miR-1305. MiR-1305 overexpression repressed the malignant phenotypes of LUAD cells, while SALL4 enhancement abated the effects. CircSFMBT2 aggravated the progression of LUAD by the miR-1305/SALL4 axis, which might provide a diagnostic and prognostic marker for LUAD.

Chronic stress promotes non-small cell lung cancer (NSCLC) progression through circMBOAT2 upregulation mediated by CTCF

Circular RNA (circRNA) has been demonstrated to play a pivotal role in tumor development. This study aimed to investigate the regulatory mechanism of circMBOAT2 in non-small cell lung cancer (NSCLC) and its association with tumor growth induced by chronic stress. We constructed stably transfected A549 and H1299 cell lines with circMBOAT2 overexpression and knockdown. Colony formation, scratch healing, Transwell and CCK-8 assays were conducted to evaluate the effects of circMBOAT2 in the presence or absence of norepinephrine (NE) treatment on the proliferation, migration, and invasion of NSCLC cells, respectively. Additionally, A chronic unpredictable mild stress (CUMS)-induced depression with heterotopic transplantation LLC and injection of antisense oligonucleotides (ASOs) targeting circMBOAT2 mouse model was established to evaluate the effect of chronic stress on tumorigenesis via circMBOAT2. Moreover, we investigated the regulatory effect of CCCTC binding factor (CTCF) on circMBOAT2 expression through in vivo and in vitro silencing of CTCF. Our results revealed a significant upregulation of circMBOAT2 in NSCLC cell lines and tumor tissues. circMBOAT2 knockdown inhibited the proliferation, migration, and invasion of NSCLC cells, while NE treatment reversed the cell suppression effect caused by circMBOAT2 knockdown. Notably, CUMS promoted tumor growth, while silencing circMBOAT2 inhibited tumor growth in vivo. Furthermore, we identified CTCF as the upstream regulator of circMBOAT2, which exhibited upregulation in NSCLC cells and tissues. Knockdown of CTCF reversed the promotional effect of CUMS on circMBOAT2 expression and tumor growth. Our findings provide evidence that CTCF mediates chronic stress in promoting of NSCLC progression through circMBOAT2. circMBOAT2 may serve as a potential biomarker and therapeutic target for NSCLC as well as the treatment of comorbid depression in NSCLC patients.

The Role of circHIPK3 in Tumorigenesis and Its Potential as a Biomarker in Lung Cancer

Lung cancer treatment and detection can be improved by the identification of new biomarkers. Novel approaches in investigating circular RNAs (circRNAs) as biomarkers have yielded promising results. A circRNA molecule circHIPK3 was found to be widely expressed in non-small-cell lung cancer (NSCLC) cells, where it plays a crucial role in lung cancer tumorigenesis. CircHIPK3 promotes lung cancer progression by sponging oncosuppressive miRNAs such as miR-124, miR-381-3p, miR-149, and miR-107, which results in increased cell proliferation, migration, and resistance to therapies. Inhibiting circHIPK3 has been demonstrated to suppress tumour growth and induce apoptosis, which suggests its potential use in the development of new lung cancer treatment strategies targeting circHIPK3-related pathways. As a biomarker, circHIPK3 shows promise for early detection and monitoring of lung cancer. CircHIPK3 increased expression levels in lung cancer cells, and its potential link to metastasis risk highlights its clinical relevance. Given the promising preliminary findings, more clinical trials are needed to validate circHIPK3 efficacy as a biomarker. Moreover, future research should determine if the mechanisms discovered in NSCLC apply to small cell lung cancer (SCLC) to investigate circHIPK3-targeted therapies for SCLC.

Unleashing the potential of mRNA therapeutics for inherited neurological diseases

Neurological monogenic loss-of-function diseases are hereditary disorders resulting from gene mutations that decrease or abolish the normal function of the encoded protein. These conditions pose significant therapeutic challenges, which may be resolved through the development of innovative therapeutic strategies. RNA-based technologies, such as mRNA replacement therapy, have emerged as promising and increasingly viable treatments. Notably, mRNA therapy exhibits significant potential as a mutation-agnostic approach that can address virtually any monogenic loss-of-function disease. Therapeutic mRNA carries the information for a healthy copy of the defective protein, bypassing the problem of targeting specific genetic variants. Moreover, unlike conventional gene therapy, mRNA-based drugs are delivered through a simplified process that requires only transfer to the cytoplasm, thereby reducing the mutagenic risks related to DNA integration. Additionally, mRNA therapy exerts a transient effect on target cells, minimizing the risk of long-term unintended consequences. The remarkable success of mRNA technology for developing coronavirus disease 2019 vaccines has rekindled interest in mRNA as a cost-effective method for delivering therapeutic proteins. However, further optimization is required to enhance mRNA delivery, particularly to the CNS, while minimizing adverse drug reactions and toxicity. In this comprehensive review, we delve into past, present and ongoing applications of mRNA therapy for neurological monogenic loss-of-function diseases. We also discuss the promises and potential challenges presented by mRNA therapeutics in this rapidly advancing field. Ultimately, we underscore the full potential of mRNA therapy as a game-changing therapeutic approach for neurological disorders.

Research progress of circular RNAs in myocardial ischemia

Circular RNAs (circRNAs) are a type of single-stranded RNA that forms a covalently closed continuous loop. Its structure, stability, properties, and cell- and tissue-specificity have gained considerable recognition in the research and clinical sectors, as its role has been observed in different diseases, such as cardiovascular diseases, cancers, and central nervous system diseases, etc. Cardiovascular disease is still named as the number one cause of death globally, with myocardial ischemia (MI) accounting for 15 % of mortality annually. A number of circRNAs have been identified and are being studied for their ability to reduce MI by inhibiting the molecular mechanisms associated with myocardial ischemia reperfusion injury, such as inflammation, oxidative stress, autophagy, apoptosis, and so on. CircRNAs play a significant role as crucial regulatory elements at transcriptional levels, regulating different proteins, and at posttranscriptional levels, having interactions with RNA-binding proteins, ribosomal proteins, micro-RNAS, and long non-coding RNAS, making it possible to exert their effects through the circRNA-miRNA-mRNA axis. CircRNAs are a potential novel biomarker and therapeutic target for myocardial ischemia and cardiovascular diseases in general. The purpose of this review is to summarize the relationship, function, and mechanism observed between circRNAs and MI injury, as well as to provide directions for future research and clinical trials.

Predicting circRNA-RBP Binding Sites Using a Hybrid Deep Neural Network

Circular RNAs (circRNAs) are non-coding RNAs generated by reverse splicing. They are involved in biological process and human diseases by interacting with specific RNA-binding proteins (RBPs). Due to traditional biological experiments being costly, computational methods have been proposed to predict the circRNA-RBP interaction. However, these methods have problems of single feature extraction. Therefore, we propose a novel model called circ-FHN, which utilizes only circRNA sequences to predict circRNA-RBP interactions. The circ-FHN approach involves feature coding and a hybrid deep learning model. Feature coding takes into account the physicochemical properties of circRNA sequences and employs four coding methods to extract sequence features. The hybrid deep structure comprises a convolutional neural network (CNN) and a bidirectional gated recurrent unit (BiGRU). The CNN learns high-level abstract features, while the BiGRU captures long-term dependencies in the sequence. To assess the effectiveness of circ-FHN, we compared it to other computational methods on 16 datasets and conducted ablation experiments. Additionally, we conducted motif analysis. The results demonstrate that circ-FHN exhibits exceptional performance and surpasses other methods. circ-FHN is freely available at https://github.com/zhaoqi106/circ-FHN .

WTAP-mediated m6A modification of circ_0032463 promotes osteosarcoma progression by sponging miR-145-5p and regulating GFRA1 expression

Osteosarcoma (OS) is the most frequent bone malignancy in humans. Previous evidence suggest that circ_0032463 is an oncogenic circular RNA (circRNA) in various cancers, including OS. However, the molecular mechanism of circ_0032463 involved in OS is still unclear. Circ_0032463, microRNA-145-5p (miR-145-5p), GDNF receptor alpha 1 (GFRA1), and Wilms tumor 1-associated protein (WTAP) levels were determined using real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, migration, invasion, and angiogenesis were analyzed using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays. Western blot analysis was performed to measure matrix metalloproteinase 2 (MMP2), MMP9, GFRA1, and WTAP protein levels. Binding between miR-145-5p and circ_0032463 or GFRA1 was confirmed using a dual-luciferase reporter and pull-down assay. The biological role of circ_0032463 on OS cell growth was also analyzed using a xenograft tumor model in vivo. Methylated RNA immunoprecipitation assay validated the interaction between WTAP and circ_0032463. Circ_0032463, GFRA1, and WTAP levels were increased, and miR-145-5p was decreased in OS tissues and cells. Circ_0032463 deficiency might hinder OS cell proliferation, migration, invasion, angiogenesis, and promote apoptosis in vitro. Mechanically, circ_0032463 worked as a miR-145-5p sponge to increase GFRA1 expression. Repression of circ_0032463 knockdown on tumor cell growth was proved in vivo. Besides, N6-methyladenosine (m6A) modification facilitates the biogenesis of circ_0032463. Taken together, m6A-mediated biogenesis of circ_0032463 facilitates OS cell malignant biological behavior partly via regulating the miR-145-5p/GFRA1 axis, suggesting a promising molecular marker for OS treatment.

CircRNAs as upstream regulators of miRNA//HMGA2 axis in human cancer

High mobility group protein A2 (HMGA2) is widely recognized as a chromatin-binding protein, whose overexpression is observed in nearly all human cancers. It exerts its oncogenic effects by influencing various cellular processes such as the epithelial-mesenchymal transition, cell differentiation, and DNA damage repair. MicroRNA (miRNA) serves as a pivotal gene expression regulator, concurrently modulating multiple genes implicated in cancer progression, including HMGA2. It also serves as a significant biomarker for cancer. Circular RNA (circRNA) plays a crucial role in gene regulation primarily by sequestering miRNAs and impeding their ability to enhance the expression of other genes, including HMGA2. Increasingly, studies have underscored the vital role of miRNA/HMGA2 interactions in cancer. Given the significance of circRNA as an upstream regulatory mediator and the complexity of regulatory mechanisms, we hereby present a comprehensive overview of the pivotal role of circRNAs as upstream regulators of the miRNA//HMGA2 axis in human cancers. This insight may herald a novel direction for future cancer research.

Gastrin-related circRNA_0017065 promotes the proliferation and metastasis of colorectal cancer through the miR-3174/RBFOX2 axis

Gastrin is a gastrointestinal peptide hormone that plays an important role in the progression of colorectal cancer (CRC). However, the molecular mechanism remains unclear. In this study, we identified gastrin-related circRNAs via high-throughput sequencing and selected circRNA_0017065 as the research focus. We further studied its specific role and molecular mechanism in the progression of CRC. Knockdown and overexpression of circRNA_0017065 were performed, and the biological function of circRNA_0017065 in CRC progression was studied via in vitro and in vivo functional experiments. The potential downstream target genes were subsequently identified via screening of databases and gene chip data. The expression of circRNA_0017065 in tumour tissues was significantly upregulated compared with that in adjacent normal tissues. In vitro and in vivo functional experiments revealed that the proliferation and migration of CRC cells were significantly suppressed after circRNA_0017065 knockdown, while apoptosis was promoted. After overexpression of circRNA_0017065, the proliferation and migration of CRC cells were significantly promoted, while apoptosis was inhibited. Mechanistic studies revealed that circRNA_0017065 can act as a sponge for miR-3174 and promote CRC progression via the miR-3174/RBFOX2 axis. In general, gastrin-related circRNA_0017065 plays a key role in the occurrence and development of CRC and is expected to be a potential molecular target for the treatment of CRC metastasis.

Circular RNA hsa_circ_0000467 promotes colorectal cancer progression by promoting eIF4A3-mediated c-Myc translation

BACKGROUND

Colorectal cancer (CRC) is the second most common malignant tumor worldwide, and its incidence rate increases annually. Early diagnosis and treatment are crucial for improving the prognosis of patients with colorectal cancer. Circular RNAs are noncoding RNAs with a closed-loop structure that play a significant role in tumor development. However, the role of circular RNAs in CRC is poorly understood.

METHODS

The circular RNA hsa_circ_0000467 was screened in CRC circRNA microarrays using a bioinformatics analysis, and the expression of hsa_circ_0000467 in CRC tissues was determined by in situ hybridization. The associations between the expression level of hsa_circ_0000467 and the clinical characteristics of CRC patients were evaluated. Then, the role of hsa_circ_0000467 in CRC growth and metastasis was assessed by CCK8 assay, EdU assay, plate colony formation assay, wound healing assay, and Transwell assay in vitro and in a mouse model of CRC in vivo. Proteomic analysis and western blotting were performed to investigate the effect of hsa_circ_0000467 on c-Myc signaling. Polysome profiling, RT‒qPCR and dual-luciferase reporter assays were performed to determine the effect of hsa_circ_0000467 on c-Myc translation. RNA pull-down, RNA immunoprecipitation (RIP) and immunofluorescence staining were performed to assess the effect of hsa_circ_0000467 on eIF4A3 distribution.

RESULTS

In this study, we found that the circular RNA hsa_circ_0000467 is highly expressed in colorectal cancer and is significantly correlated with poor prognosis in CRC patients. In vitro and in vivo experiments revealed that hsa_circ_0000467 promotes the growth and metastasis of colorectal cancer cells. Mechanistically, hsa_circ_0000467 binds eIF4A3 to suppress its nuclear translocation. In addition, it can also act as a scaffold molecule that binds eIF4A3 and c-Myc mRNA to form complexes in the cytoplasm, thereby promoting the translation of c-Myc. In turn, c-Myc upregulates its downstream targets, including the cell cycle-related factors cyclin D2 and CDK4 and the tight junction-related factor ZEB1, and downregulates E-cadherin, which ultimately promotes the growth and metastasis of CRC.

CONCLUSIONS

Our findings revealed that hsa_circRNA_0000467 plays a role in the progression of CRC by promoting eIF4A3-mediated c-Myc translation. This study provides a theoretical basis and molecular target for the diagnosis and treatment of CRC.

Circ_0000395 promotes cell growth, metastasis and oxaliplatin resistance by regulating miR-153-5p/MYO6 in colorectal cancer

BACKGROUND

Circular RNAs (circRNAs) are involved in the regulation of colorectal cancer (CRC) progression and chemoresistence. Here, we attempted to reveal the function and mechanism of circ_0000395 in CRC chemoresistence.

METHODS

The expression levels of circ_0000395, microRNA (miR)-153-5p, and myosin VI (MYO6) were determined by quantitative real-time PCR. Cell growth, metastasis and oxaliplatin resistance were evaluated via EdU assay, colony formation assay, flow cytometry, transwell assay, and cell counting kit 8 assay. Xenograft tumor model was adopted to evaluate the role of circ_0000395 on CRC tumor growth and oxaliplatin sensitivity. Protein expression of drug-resistance markers and MYO6 was analyzed by western blot. The target relationship between miR-153-5p and circ_0000395 or MYO6 was validated via dual-luciferase reporter assay and RIP assay.

RESULTS

Circ_0000395 expression was enhanced in CRC tissues and cells. Silencing of circ_0000395 repressed CRC cell proliferation, migration and invasion, while promoted apoptosis and oxaliplatin sensitivity. Besides, circ_0000395 knockdown also reduced CRC tumor growth and enhanced the sensitivity of tumor to oxaliplatin. Additionally, circ_0000395 acted as a sponge for miR-153-5p, and miR-153-5p targeted MYO6. Functional experiments suggested that miR-153-5p inhibitor or MYO6 overexpression could reverse the suppressive effect of circ_0000395 knockdown on CRC cell growth, metastasis and oxaliplatin resistance.

CONCLUSION

Circ_0000395 promoted CRC cell growth, metastasis and oxaliplatin resistance via the miR-153-5p/MYO6 axis, which might provide new insights into the treatment of CRC.

Structure and Functions of HMGB3 Protein

HMGB3 protein belongs to the group of HMGB proteins from the superfamily of nuclear proteins with high electrophoretic mobility. HMGB proteins play an active part in almost all cellular processes associated with DNA-repair, replication, recombination, and transcription-and, additionally, can act as cytokines during infectious processes, inflammatory responses, and injuries. Although the structure and functions of HMGB1 and HMGB2 proteins have been intensively studied for decades, very little attention has been paid to HMGB3 until recently. In this review, we summarize the currently available data on the molecular structure, post-translational modifications, and biological functions of HMGB3, as well as the possible role of the ubiquitin-proteasome system-dependent HMGB3 degradation in tumor development.

CircSLC25A16 facilitates the development of non-small-cell lung cancer through the miR-335-5p/CISD2 axis

BACKGROUND

Non-small-cell lung cancer (NSCLC) is a common malignancy with high morbidity and mortality. Circular RNAs are widely involved in NSCLC progression. However, the mechanism of circSLC25A16 in NSCLC has not been reported.

METHODS

The expressions of circSLC25A16, microRNA-335-5p (miR-335-5p), and CDGSH iron-sulfur domain-containing protein 2 (CISD2) were monitored by quantitative real-time fluorescence polymerase chain reaction. Western blot was also carried out to measure the protein levels of CISD2, hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA). For functional analysis, cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine, flow cytometry, transwell, and wound healing assays were utilized to examine cell proliferation, apoptosis, and migration. Glucose uptake and lactate production were detected using commercial kits. The relationship between miR-335-5p and circSLC25A16 or CISD2 was verified by dual-luciferase reporter and RNA immunoprecipitation assays. Furthermore, tumor xenograft was established to explore the function of circSLC25A16 in vivo.

RESULTS

CircSLC25A16 and CISD2 were overexpressed in NSCLC, but miR-335-5p was downregulated. CircSLC25A16 acted as a miR-335-5p sponge, and silencing of circSLC25A16 arrested cell proliferation, migration, and glycolysis, and promoted apoptosis, but these impacts were resumed by miR-335-5p inhibition. CISD2 was a miR-335-5p target, and overexpression of CISD2 abolished the suppressive function of miR-335-5p mimic on the malignant behavior of NSCLC cells. CircSLC25A16 could adsorb miR-335-5p to mediate CISD2 expression. Additionally, silencing circSLC25A16 restrained the growth of NSCLC tumor xenograft in vivo.

CONCLUSION

CircSLC25A16 facilitated NSCLC progression via the miR-335-5p/CISD2 axis, implying that circSLC25A16 may serve as a novel biomarker for NSCLC treatment.

EIF4A3-negatively driven circular RNA β-catenin (circβ-catenin) promotes colorectal cancer progression via miR-197-3p/CTNND1 regulatory axis

BACKGROUND

Circβ-catenin, our first reported circRNA, has been reported to mediate tumorigenesis in various cancers. However, its biological functions and underlying mechanisms in colorectal cancer (CRC) remain unknown.

METHODS

The qRT-PCR examination was used to detect the expression of circβ-catenin, miR-197-3p, and CTNND1 in cells and human tissues. Western blot was conducted to detect the protein expression levels. The biological function of circβ-catenin was verified by MTT, colony formation, wound healing, and transwell assays. The in vivo effects of circβ-catenin were verified by nude mice xenograft and metastasis models. The regulatory network of circβ-catenin/miR-197-3p/CTNND1 was confirmed via dual-luciferase reporter and RIP assays.

RESULTS

In the present study, circβ-catenin was found to promote CRC cell proliferation and metastasis in vitro and in vivo. Mechanistically, circβ-catenin served as miRNA decoy to directly bind to miR-197-3p, then antagonized the repression of the target gene CTNND1, and eventually promoted the malignant phenotype of CRC. More interestingly, the inverted repeated Alu pairs termed AluJb1/2 and AluY facilitated the biogenesis of circβ-catenin, which could be partially reversed by EIF4A3 binding to Alu element AluJb2.

CONCLUSIONS

Our findings illustrated a novel mechanism of circβ-catenin in modulating CRC tumorigenesis and metastasis, which provides a potential therapeutic target for CRC patients.

Gypenoside A Protects Human Myocardial Cells from Ischemia/Reperfusion Injury via the circ_0010729/miR-370-3p/RUNX1 Axis

Ischemia/reperfusion (I/R) injury is one of the major causes of cardiovascular disease. Gypenoside A (GP), the main active component of Gynostemma pentaphyllum, alleviates myocardial I/R injury. Circular RNAs (circRNAs) and microRNAs (miRNAs) are involved in the I/R injury. We explored the protective effect of GP on human cardiomyocytes (HCMs) via the circ_0010729/miR-370-3p/RUNX1 axis. Overexpression of circ_0010729 abolished the effects of GP on HMC, such as suppression of apoptosis and increase in cell viability and proliferation. Overexpression of miR-370-3p reversed the effect of circ_0010729 overexpression, resulting in the stimulation of HMC viability and proliferation and inhibition of apoptosis. The knockdown of miR-370-3p suppressed the effects of GP in HCMs. RUNX1 silencing counteracted the effect of miR-370-3p knockdown and maintained GP-induced suppression of apoptosis and stimulation of HMC viability and proliferation. The levels of RUNX1 mRNA and protein were reduced in cells expressing miR-370-3p. In conclusion, this study confirmed that GP alleviated the I/R injury of myocardial cell via the circ_0010729/miR-370-3p/RUNX1 axis.

Potential therapeutic strategy for cancer: Multi-dimensional cross-talk between circRNAs and parental genes

In many ways, circular RNAs (circRNAs) have been demonstrated to be crucial in the onset and advancement of cancer throughout the last ten years and have become a new focus of intense research in the field of RNAs. Accumulating studies have demonstrated that circRNAs can regulate parental gene expression via a variety of biological pathways. Furthermore, research into the complex interactions between circRNAs and their parental genes will shed light on their biological roles and open up new avenues for circRNAs' potential clinical translational uses. However, to date, multi-dimensional cross-talk between circRNAs and parental genes have not been systematically elucidated. Particularly intriguing is circRNA's exploration of tumor targeting, and potential therapeutic uses based on the parental gene regulation perspective. Here, we discuss their biogenesis, take a fresh look at the molecular mechanisms through which circRNAs control the expression of their parental genes in cancer. We further highlight We further highlight the latest circRNA clinical translational applications, including prognostic diagnostic markers, cancer vaccines, gDNA, and so on. Demonstrating the potential benefits and future applications of circRNA therapy.

The Combination of circEPSTI1 and MIF Offers Diagnostic Value for Endometrial Cancer

Background

Circular RNAs (circRNAs) exhibit unique patterns of expression and high levels of stability in patient plasma samples such that they represent ideal non-invasive biomarkers that can be leveraged to detect a wide array of diseases including endometrial cancer (EC). This study was designed to identify circRNAs with potential diagnostic utility in serum samples from EC patients while also evaluating the utility of macrophage migration inhibitory factor (MIF) as a biomarker when screening for this form of cancer in the clinic.

Methods

Levels of circEPSTI1 and MIF were assessed in the plasma of EC patients and healthy subjects (n=186 each) through qPCR and ELISAs. The diagnostic utility of these biomarkers was assessed with receiver operating characteristic curve (ROC) analyses.

Results

Relative to healthy subjects, EC patient serum contained significantly elevated circEPSTI1 and MIF. An association was noted between circEPSTI1 expression in stages, histologic grade, and residual tumor. ROC curves confirmed that serum circEPSTI1 levels distinguished between controls and patients with EC with an Area of 0.835 and serum MIF levels distinguished between controls and patients with EC with an Area of 0.6646. When instead diagnosing patients based on the combination of MIF and circEPSTI1, the Area further rose to 0.8604.

Conclusion

Assessing the combination of circEPSTI1 and MIF may be a viable approach to reliably diagnosing EC.

CircRNA-associated ceRNA regulatory networks as emerging mechanisms governing the development and biophysiopathology of epilepsy

The etiology of epilepsy is ascribed to the synchronized aberrant neuronal activity within the brain. Circular RNAs (circRNAs), a class of non-coding RNAs characterized by their circular structures and covalent linkage, exert a substantial influence on this phenomenon. CircRNAs possess stereotyped replication, transience, repetitiveness, and paroxysm. Additionally, MicroRNA (miRNA) plays a crucial role in the regulation of diverse pathological processes, including epilepsy. CircRNA is of particular significance due to its ability to function as a competing endogenous RNA, thereby sequestering or inhibiting miRNA activity through binding to target mRNA. Our review primarily concentrates on elucidating the pathological and functional roles, as well as the underlying mechanisms, of circRNA-miRNA-mRNA networks in epilepsy. Additionally, it explores the potential utility of these networks for early detection and therapeutic intervention.

Hsa_circ_0010882 facilitates hepatocellular carcinoma progression by modulating M1/M2 macrophage polarization

Hepatocellular carcinoma (HCC) is one common malignant tumour with a high immunosuppressive tumour microenvironment and poor outcomes. This study investigated the influence of hsa_circ_0010882 on M1/M2 macrophage polarization in the progression of HCC. A total of 125 paired tissue specimens from HCC patients who underwent hepatectomy were collected. M1 and M2 phenotypes macrophages were induced using THP-1. After co-cultured with macrophages and transfected HCC cells, the viability, migration and invasion of HCC cells were detected by cellular experiments. Bioinformatic databases and dual-luciferase reporter assays were used to predict and validate the interaction between circ_0010882 and miR-382. Expression of circ_0010882 was increased in HCC tissues and associated with shorter overall survival outcomes. The mRNA expression of M2 macrophage markers Arg-1, CD163 and CD206 were elevated in HCC tissues. Interfering with circ_0010882 increased M1-type macrophage markers (TNF-α and iNOS) while decreasing M2-type macrophage markers (Arg-1 and CD206). Silencing of circ_0010882 strengthened the capacity of M1 macrophages to suppress HCC cell viability, migration capacities and invasion potential while reducing the ability of M2 macrophages to promote above cellular abilities. MiR-382 was a direct target miRNA of circ_0010882. The circ_0010882 expression was increased in HCC tissues and associated with poor prognosis of HCC patients. Silencing of circ_0010882 inhibits macrophage M2 polarization in HCC progression by regulating miR-382 expression. Circ_0010882 may serve as a biomarker to provide novel strategies for the treatment of HCC and patient rehabilitation, thereby improving the prognosis of patients.

CircNRD1 elevates THAP domain containing 11 through sequestering microRNA-421 to inhibit gastric cancer growth and tumorigenesis

We explored the role and mechanism of circular RNAcircNRD1 in gastric cancer (GC) progression, aiming to identify new bio-markers for the treatment and prognosis of GC patients. The RNA expression was examined by reverse transcription-quantitative polymerase chain reaction. Cell proliferation, migration and invasion were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, scratch assay and transwell assay. Western blot assay was conducted for protein expression measurement. Dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays were conducted to verify the interaction between microRNA-421 (miR-421) and circNRD1 or THAP domain containing 11 (THAP11). Xenograft tumor model was established to perform in vivo experiments. CircNRD1 was notably downregulated in GC tissues and cell lines. Additionally, decreased circNRD1 level was closely associated with advanced tumor stage and dismal prognosis in GC patients. CircNRD1 overexpression suppressed the proliferation and metastasis of GC cells. CircNRD1 acted as a molecular sponge for miR-421 in GC cells, and the antitumor impacts of circNRD1 overexpression in GC cells could be alleviated by miR-421 overexpression. miR-421 directly targeted THAP11, and circNRD1 could up-regulate THAP11 expression in GC cells through sponging miR-421. THAP11 knockdown reversed circNRD1 overexpression-induced tumor suppressing effects in GC cells. CircNRD1 overexpression significantly blocked tumor growth in vivo. CircNRD1 suppressed the proliferation and metastasis of GC cells in vitro and blocked tumor growth in vivo via modulating miR-421/THAP11 axis.

The role of ncRNAs in depression

Depressive disorders have a significant impact on public health, and depression have an unsatisfactory recurrence rate and are challenging to treat. Non-coding RNAs (ncRNAs) are RNAs that do not code protein, which have been shown to be crucial for transcriptional regulation. NcRNAs are important to the onset, progress and treatment of depression because they regulate various physiological functions. This makes them distinctively useful as biomarkers for diagnosing and tracking responses to therapy among individuals with depression. It is important to seek out and summarize the research findings on the impact of ncRNAs on depression since significant advancements have been made in this area recently. Hence, we methodically outlined the findings of published researches on ncRNAs and depression, focusing on microRNAs. Above all, this review aims to improve our understanding of ncRNAs and provide new insights of the diagnosis and treatment of depression.

Hsa_circ_0001615 downregulation inhibits esophageal cancer development through miR-142-5p/β-catenin

Background

Recent studies have found that circular RNAs (circRNAs) play important roles in tumorigenesis. This study aimed to determine the function and potential mechanisms of hsa_circ_0001615 in esophageal cancer.

Methods

Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to validate the expression of hsa_circ_0001615 and miR-142-5p. Subsequently, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt, flow cytometry, clone formation, and transwell assays were used to assess the function of hsa_circ_0001615. Furthermore, qRT-PCR and Western blot analysis were used to verify cyclin D1, Bcl-2 associated X, B-cell lymphoma/leukemia gene-2, and β-catenin levels. Circular RNA Interactome was used to estimate the binding site between hsa_circ_0001615 and miR-142-5p. Additionally, dual-luciferase reporter assays were used to determine whether miR-142-5p was a direct target of hsa_circ_0001615. Pearson correlation analysis was used to explore the relationship between miR-142-5p and hsa_circ_0001615.

Results

In esophageal cancer, the expressions of hsa_circ_0001615 and miR-142-5p were increased and decreased, respectively. Hsa_circ_0001615 inhibition significantly reduced the proliferation, migration, and invasion but increased the apoptosis of esophageal cancer cells. Additionally, hsa_circ_0001615 knockdown increased miR-142-5p expression but decreased β-catenin expression. MiR-142-5p was a direct target of hsa_circ_0001615.

Conclusion

Hsa_circ_0001615 knockdown could mediate antitumor effects through the miR-142-5p/β-catenin pathway.

Circ_0008657 regulates lung DNA damage induced by hexavalent chromium through the miR-203a-3p/ATM axis

Hexavalent chromium [Cr (VI)] is an important environmental pollutant and may cause lung injury when inhaled into the human body. Cr (VI) is genotoxic and can cause DNA damage, although the underlying epigenetic mechanisms remain unclear. To simulate the real-life workplace exposure to Cr (VI), we used a novel exposure dose calculation method. We evaluated the effect of Cr (VI) on DNA damage in human bronchial epithelial cells (16HBE and BEAS-2B) by calculating the equivalent real-time exposure dose of Cr (VI) (0 to 10 μM) in an environmental population. Comet experiments and olive tail moment measurements revealed increased DNA damage in cells exposed to Cr (VI). Cr (VI) treatment increased nuclear γ-H2AX foci and γ-H2AX protein expression, and caused DNA damage in the lung tissues of mice. An effective Cr (VI) dose (6 μM) was determined and used for cell treatment. Cr (VI) exposure upregulated circ_0008657, and knockdown of circ_0008657 decreased Cr (VI)-induced DNA damage, whereas circ_0008657 overexpression had the opposite effect. Mechanistically, we found that circ_0008657 binds to microRNA (miR)-203a-3p and subsequently regulates ATM serine/threonine kinase (ATM), a key protein involved in homologous recombination repair downstream of miR-203a-3p, thereby regulating DNA damage induced by Cr (VI). The present findings suggest that circ_0008657 competitively binds to miR-203a-3p to activate the ATM pathway and regulate the DNA damage response after environmental chemical exposure in vivo and in vitro.

LMGATCDA: Graph Neural Network With Labeling Trick for Predicting circRNA-Disease Associations

Previous studies have proven that circular RNAs (circRNAs) are inextricably connected to the etiology and pathophysiology of complicated diseases. Since conventional biological research are frequently small-scale, expensive, and time-consuming, it is essential to establish an efficient and reasonable computation-based method to identify disease-related circRNAs. In this article, we proposed a novel ensemble model for predicting probable circRNA-disease associations based on multi-source similarity information(LMGATCDA). In particular, LMGATCDA first incorporates information on circRNA functional similarity, disease semantic similarity, and the Gaussian interaction profile (GIP) kernel similarity as explicit features, along with node-labeling of the three-hop subgraphs extracted from each linked target node as graph structural features. After that, the fused features are used as input, and further implied features are extracted by graph sampling aggregation (GraphSAGE) and multi-hop attention graph neural network (MAGNA). Finally, the prediction scores are obtained through a fully connected layer. With five-fold cross-validation, LMGATCDA demonstrated excellent competitiveness against gold standard data, reaching 95.37% accuracy and 91.31% recall with an AUC of 94.25% on the circR2Disease benchmark dataset. Collectively, the noteworthy findings from these case studies support our conclusion that the LMGATCDA model can provide reliable circRNA-disease associations for clinical research while helping to mitigate experimental uncertainties in wet-lab investigations.

circ_HMGCS1 modulates hepatocellular carcinoma chemoresistance via miR-338-5p/IL-7 pathway

Hepatocellular cancer is one of the most serious types of cancer in the world, with high incidence and mortality rates. Most HCC patients with long-term chemotherapy develop chemoresistance, leading to a poor prognosis. However, the underlying mechanism of circRNAs in HCC chemoresistance remains unclear. Our research found that circ_0072391(circ_HMGCS1) expression was significantly upregulated in cisplatin-resistant HCC cells. The silence of circ_HMGCS1 attenuated the cisplatin resistance in HCC. Results showed that circ_HMGCS1 regulated the expression of miR-338-5p via acting as microRNA sponges. Further study confirmed that miR-338-5p regulated the expression of IL-7. IL-7 could remodel the immune system by improving T-cell function and antagonising the immunosuppressive network. IL-7 is an ideal target used to enhance the function of the immune system. circ_HMGCS1 exerts its oncogenic function through the miR-338-5p/IL-7 pathway. Inhibition of circ_HMGCS1/miR-338-5p/IL-7 could effectively attenuate the chemoresistance of HCC. IL-7 might be a promising immunotherapy target for HCC cancer treatment.

CircRUNX1 drives the malignant phenotypes of lung adenocarcinoma through mediating the miR-5195-3p/HMGB3 network

BACKGROUND

Circular RNAs (circRNAs) are key factors in the regulation of cancer progression. However, the role of circRUNX1 in lung adenocarcinoma (LUAD) progression is unclear.

METHODS

The expression levels of circRUNX1, microRNA (miR)-5195-3p, and high-mobility group protein B3 (HMGB3) were detected by quantitative real-time PCR. Cell proliferation, migration, invasion and apoptosis were analyzed by EdU staining, colony formation assay, transwell assay and flow cytometry. Protein levels were measured using western blot analysis. The interaction between miR-5195-3p and circRUNX1 or HMGB3 was verified by dual-luciferase reporter assay and RIP assay. Animal experiments were performed to investigate the role of circRUNX1 in LUAD tumorigenesis.

RESULTS

We found that circRUNX1 was upregulated in LUAD tumor tissues and cells. CircRUNX1 knockdown suppressed LUAD cell proliferation and metastasis, while promoted apoptosis. In terms of mechanism, we found that circRUNX1 could sponge miR-5195-3p, and miR-5195-3p inhibitor abolished the regulation of circRUNX1 knockdown on LUAD cell proliferation, metastasis and apoptosis. In addition, miR-5195-3p could target HMGB3, and HMGB3 overexpression reversed the inhibition effect of miR-5195-3p on LUAD progression. Moreover, circRUNX1 knockdown reduced LUAD tumorigenesis.

CONCLUSION

CircRUNX1 facilitated LUAD proliferation and metastasis by regulating the miR-5195-3p/HMGB3 axis, suggesting that it might be a possible therapeutic target for LUAD.

CircRNA ITCH Inhibits Epithelial-Mesenchymal Transformation and Promotes Apoptosis in Papillary Thyroid Carcinoma via miR-106a-5p/JAZF1 Axis

Circular RNA ITCH (circ-ITCH) is implicated in papillary thyroid carcinoma (PTC) development. Nevertheless, the more detailed molecular mechanism remains uncovered. The transcriptional level of circ-ITCH was tested via quantitative real-time PCR. Transwell assay was introduced to assess the migrative and invasive abilities of cells. RNA interference technology was employed to reduce the level of circ-ITCH as well as JAZF1 in PTC cells. Western blot assay was utilized to reveal the content of JAZF1 and proteins related to epithelial-mesenchymal transformation (EMT) progression. Circ-ITCH was downregulated in PTC tissues as well as cells. Overexpression of circ-ITCH suppressed EMT, migration, invasion, facilitated apoptosis in PTC cells, while silencing circ-ITCH exhibited reversed effects. Additionally, miR-106a-5p was the target of circ-ITCH and negatively regulated through circ-ITCH. MiR-106a-5p mimic partly eliminated the influences of overexpressed circ-ITCH in PTC cells. Moreover, JAZF1 could interact with miR-106a-5p, then it was regulated via circ-ITCH. Silencing JAZF1 partially counteracted the role of circ-ITCH in PTC cells progress. This study uncovered that circ-ITCH suppressed the development of PTC cells at least partly by mediating miR-106a-5p/JAZF1 network.

ADAMTS Gene-Derived circRNA Molecules in Non-Small-Cell Lung Cancer: Expression Profiling, Clinical Correlations and Survival Analysis

The present study examines the relationship between circular RNA (circRNA) derived from three genes of the family a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs): ADAMTS6, ADAMTS9 and ADAMTS12 and the host gene expression in non-small-cell lung cancer (NSCLC) with regard to various clinical factors. Notably, an association was identified between ADAMTS12 expression and specific circRNA molecules, as well as certain expression patterns of ADAMTS6 and its derived circRNA that were specific to histopathological subtypes. The survival analysis demonstrated that a lower ADAMTS6 expression in squamous cell carcinoma was associated with extended survival. Furthermore, the higher ADAMTS9 expression was linked to prolonged survival, while the overexpression of ADAMTS12 was correlated with a shorter survival. These findings suggest that circRNA molecules may serve as potential diagnostic or prognostic biomarkers for NSCLC, highlighting the importance of considering molecular patterns in distinct cancer subtypes.

Circ_0059457 Promotes Proliferation, Metastasis, Sphere Formation and Glycolysis in Breast Cancer Cells by Sponging miR-140-3p to Regulate UBE2C

Circular RNA (circRNA) has been confirmed to regulate breast cancer (BC) progression. However, the role of circ_0059457 in BC progression is still unclear.The expression of circ_0059457, taspase 1 (TASP1), microRNA (miR)-140-3p and ubiquitin-binding enzyme E2C (UBE2C) was detected by quantitative real-time PCR. Cell proliferation, migration, invasion and sphere formation ability were assessed by cell counting kit-8 assay, EdU assay, wound healing assay, transwell assay and sphere formation assay. Cell glycolysis was assessed by detecting glucose uptake, lactate levels and ATP/ADP ratio. Dual-luciferase reporter assay, RIP assay, RNA pull-down assay were used to validate RNA interaction. Xenograft tumor model to assess the effect of circ_0059457 on BC tumor growth in vivo. Circ_0059457 had elevated expression in BC tissues and cells. Circ_0059457 knockdown inhibited BC cell proliferation, metastasis, sphere formation ability, and glycolysis. In terms of mechanism, circ_0059457 sponged miR-140-3p, and miR-140-3p targeted UBE2C. MiR-140-3p inhibition reversed the effect of circ_0059457 knockdown on BC cell malignant behaviors. Besides, miR-140-3p overexpression inhibited BC cell proliferation, metastasis, sphere formation ability and glycolysis, and these effects were abrogated by UBE2C enhancement. Furthermore, circ_0059457 regulated UBE2C expression through sponging miR-140-3p. Additionally, circ_0059457 knockdown obviously inhibited BC tumor growth in vivo. Circ_0059457 promoted BC progression via miR-140-3p/UBE2C axis, which provided potential target for the treatment of BC.

Hsa_circ_0031891 targets miR-579-3p to enhance HMGB1 expression and regulate PDGF-BB-induced human aortic vascular smooth muscle cell proliferation, migration, and dedifferentiation

Atherosclerosis (AS) is an underlying cause of the majority of coronary artery disease (CAD), in which proliferation, migration, and dedifferentiation of vascular smooth muscle cells (VSMCs) exert vital roles. It has been reported that circular RNAs (circRNAs) are associated with the VSMCs function. Here, we undertook to explore the biological function and mechanism of hsa_circ_0031891 in a platelet-derived growth factor-BB (PDGF-BB)-induced AS cell model. Hsa_circ_0031891 and microRNA-579-3p (miR-579-3p) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation and migration were detected using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), wound healing, and transwell assay. Protein levels of alpha-smooth muscle actin (α-SMA), smooth muscle protein 22-α (SM22-α), Osteopontin, and High mobility group box-1 (HMGB1) were determined using western blot assay. After predicting via a variety of bioinformatics software, the binding between miR-579-3p and hsa_circ_0031891 or HMGB1 was validated using dual-luciferase reporter and RNA pull-down assays. Increased hsa_circ_0031891 and HMGB1 and reduced miR-579-3p were found in CAD patients and PDGF-BB-induced human aortic vascular smooth muscle cells (HA-VSMCs). Moreover, hsa_circ_0031891 deficiency relieved PDGF-BB-mediated HA-VSMC proliferation, migration, and dedifferentiation. Mechanically, hsa_circ_0031891 modulated HMGB1 expression via sponging miR-579-3p. Hsa_circ_0031891 boosted PDGF-BB-induced proliferation, migration, and dedifferentiation partly by regulating the miR-579-3p/HMGB1 axis, hinting at a feasible therapeutic strategy for AS.

Mechanism through which the hsa-circ_0000992- hsa- miR- 936-AKT3 regulatory network promotes the PM2.5-induced inflammatory response in human bronchial epithelial cells

BACKGROUND

Studies have shown that fine particulate matter (PM2.5) remains a significant problem in developing countries and plays a critical role in the onset and progression of respiratory illnesses. Circular RNAs (circRNAs) are involved in many pathophysiological processes,but their relationship to PM2.5 pollution is largely unexplored.

OBJECTIVES

To elucidate the functional role of hsa_circ_0000992 in PM2.5-induced inflammation in a human bronchial epithelial cell line (16HBE) and to clarify whether the competing endogenous RNA (ceRNA) mechanism is involved in the interrelationships between hsa_circ_0000992 and hsa-miR-936 and the inflammatory signaling pathways.

METHODS

Detection of inflammatory factors in 16HBE cells exposed to PM2.5 by RT-qPCR and ELISA.High throughput sequencing and bioinformatics analysis methods were used to screen circRNA.The bioinformatics analysis method western blotting and dual-luciferase reporter gene system were used to verify mechanisms associated with circRNA.

RESULTS

PM2.5 cause inflammation in the 16HBE cells. High throughput sequencing and RT-qPCR result revealed that the expression of hsa_circ_0000992 was markedly up-regulated in 16HBE exposed to PM2.5. The binding sites between hsa_circ_0000992 and hsa-miR-936 was confirmed by dual-luciferase reporter gene system.Western blotting and RT-qPCR showed that hsa_circ_0000992 can interact with hsa-miR-936 to regulate AKT serine/threonine kinase 3(AKT3),thereby activating the PI3K/AKT pathway and ultimately promoting the expression of interleukin (IL)- 1β and IL-8.

CONCLUSION

PM2.5 can induce the inflammatory response in 16HBE cells by activating the PI3K/AKT pathway. The expression of hsa_circ_0000992 increased when PM2.5 stimulated 16HBE cells,and the circRNA could then regulate the inflammatory response.Hsa_circ_0000992 regulates the hsa-miR-936/AKT3 axis through the ceRNA mechanism,thereby activating the PI3K/AKT signaling pathway,increasing the expression of cellular inflammatory factors,and promoting PM2.5-induced respiratory inflammation.

DNI-MDCAP: improvement of causal MiRNA-disease association prediction based on deep network imputation

BACKGROUND

MiRNAs are involved in the occurrence and development of many diseases. Extensive literature studies have demonstrated that miRNA-disease associations are stratified and encompass ~ 20% causal associations. Computational models that predict causal miRNA-disease associations provide effective guidance in identifying novel interpretations of disease mechanisms and potential therapeutic targets. Although several predictive models for miRNA-disease associations exist, it is still challenging to discriminate causal miRNA-disease associations from non-causal ones. Hence, there is a pressing need to develop an efficient prediction model for causal miRNA-disease association prediction.

RESULTS

We developed DNI-MDCAP, an improved computational model that incorporated additional miRNA similarity metrics, deep graph embedding learning-based network imputation and semi-supervised learning framework. Through extensive predictive performance evaluation, including tenfold cross-validation and independent test, DNI-MDCAP showed excellent performance in identifying causal miRNA-disease associations, achieving an area under the receiver operating characteristic curve (AUROC) of 0.896 and 0.889, respectively. Regarding the challenge of discriminating causal miRNA-disease associations from non-causal ones, DNI-MDCAP exhibited superior predictive performance compared to existing models MDCAP and LE-MDCAP, reaching an AUROC of 0.870. Wilcoxon test also indicated significantly higher prediction scores for causal associations than for non-causal ones. Finally, the potential causal miRNA-disease associations predicted by DNI-MDCAP, exemplified by diabetic nephropathies and hsa-miR-193a, have been validated by recently published literature, further supporting the reliability of the prediction model.

CONCLUSIONS

DNI-MDCAP is a dedicated tool to specifically distinguish causal miRNA-disease associations with substantially improved accuracy. DNI-MDCAP is freely accessible at http://www.rnanut.net/DNIMDCAP/ .

CircSI-SSL: circRNA-binding site identification based on self-supervised learning

MOTIVATION

In recent years, circular RNAs (circRNAs), the particular form of RNA with a closed-loop structure, have attracted widespread attention due to their physiological significance (they can directly bind proteins), leading to the development of numerous protein site identification algorithms. Unfortunately, these studies are supervised and require the vast majority of labeled samples in training to produce superior performance. But the acquisition of sample labels requires a large number of biological experiments and is difficult to obtain.

RESULTS

To resolve this matter that a great deal of tags need to be trained in the circRNA-binding site prediction task, a self-supervised learning binding site identification algorithm named CircSI-SSL is proposed in this article. According to the survey, this is unprecedented in the research field. Specifically, CircSI-SSL initially combines multiple feature coding schemes and employs RNA_Transformer for cross-view sequence prediction (self-supervised task) to learn mutual information from the multi-view data, and then fine-tuning with only a few sample labels. Comprehensive experiments on six widely used circRNA datasets indicate that our CircSI-SSL algorithm achieves excellent performance in comparison to previous algorithms, even in the extreme case where the ratio of training data to test data is 1:9. In addition, the transplantation experiment of six linRNA datasets without network modification and hyperparameter adjustment shows that CircSI-SSL has good scalability. In summary, the prediction algorithm based on self-supervised learning proposed in this article is expected to replace previous supervised algorithms and has more extensive application value.

AVAILABILITY AND IMPLEMENTATION

The source code and data are available at https://github.com/cc646201081/CircSI-SSL.

Spleen tyrosine kinase facilitates the progression of papillary thyroid cancer regulated by the hsa_circ_0006417/miR-377-3p axis

Papillary thyroid cancer (PTC) is a prevalent malignancy worldwide. Spleen tyrosine kinase (SYK) is a crucial enzyme that participates in various biological processes, including cancer progression. This study aims to uncover the biological function of SYK in PTC. SYK expression patterns in PTC were evaluated using quantitative real time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC), and western blot. Cell function assays were performed to assess the effects of SYK on PTC. Bioinformatics analysis was conducted to identify intriguing microRNA (miRNA) and circular RNA (circRNA). Dual-Luciferase Reporter or RNA immunoprecipitation assays were used to investigate the correlation among SYK, miR-377-3p, and hsa_circ_0006417. SYK was upregulated in PTC. Overexpression of SYK exhibited a positive correlation with tumor size, lymph node metastasis, and unfavorable disease-free survival. Functional assays revealed that SYK exerted tumorigenic effect on PTC cells through mTOR/4E-BP1 pathway. Mechanistically, hsa_circ_0006417 and miR-377-3p regulated SYK expression, offering modulating its tumor-promoting effects. Collectively, SYK acts as an oncogene in PTC through mTOR/4E-BP1 pathway, which is regulated by the hsa_circ_0006417/miR-377-3p axis, thereby providing a potential alternative for PTC treatment.

A systematic analysis of circRNAs in subnuclear compartments

CircRNAs are an important class of RNAs with diverse cellular functions in human physiology and disease. A thorough knowledge of circRNAs including their biogenesis and subcellular distribution is important to understand their roles in a wide variety of processes. However, the analysis of circRNAs from total RNA sequencing data remains challenging. Therefore, we developed Calcifer, a versatile workflow for circRNA annotation. Using Calcifer, we analysed APEX-Seq data to compare circRNA occurrence between whole cells, nucleus and subnuclear compartments. We generally find that circRNAs show higher abundance in whole cells compared to nuclear samples, consistent with their accumulation in the cytoplasm. The notable exception is the single-exon circRNA circCANX(9), which is unexpectedly enriched in the nucleus. In addition, we observe that circFIRRE prevails over the linear lncRNA FIRRE in both the cytoplasm and the nucleus. Zooming in on the subnuclear compartments, we show that circRNAs are strongly depleted from nuclear speckles, indicating that excess splicing factors in this compartment counteract back-splicing. Our results thereby provide valuable insights into the subnuclear distribution of circRNAs. Regarding circRNA function, we surprisingly find that the majority of all detected circRNAs possess complete open reading frames with potential for cap-independent translation. Overall, we show that Calcifer is an easy-to-use, versatile and sustainable workflow for the annotation of circRNAs which expands the repertoire of circRNA tools and allows to gain new insights into circRNA distribution and function.

CircNEK6 promotes the progression of pancreatic ductal adenocarcinoma through targeting miR-503/CCND1 axis

PURPOSE

The present study aimed to reveal the function and underlying molecular mechanism of circRNA NIMA related kinase 6 (circNEK6) in promoting the progression of pancreatic ductal adenocarcinoma (PDAC).

METHODS

The differentially expressed circRNAs in three paired PDAC tissues and adjacent tissues were identified by RNA sequencing. CircNEK6 was screened out to further explore its relationship with the prognosis of PDAC patients. The target microRNAs and mRNAs of circNEK6 were analyzed through online databases and detected by quantitative real-time polymerase chain reaction. Cell counting kit-8 assay, clone formation assay, transwell assay, flow cytometry and western blot were used to explore the function of circNEK6 on the biological behaviors of PDAC cells. The in vivo antitumor effect of circNEK6 silencing on PDAC was investigated by nude mouse xenograft models.

RESULTS

203 differentially expressed circRNAs including circNEK6 were identified between paired PDAC tissues and adjacent tissues, and the expression level of circNEK6 was negatively correlated with the prognosis of PDAC patients. The results of in vitro experiments showed that knockdown of circNEK6 repressed the proliferation, migration and invasion, but induced the apoptosis of PDAC cells. Moreover, circNEK6 silencing inhibited tumor growth and prolonged the survival time of PDAC-bearing mice. Mechanistically, miR-503/cyclin D1 (CCND1) axis was predicted and confirmed as the target of circNEK6.

CONCLUSIONS

CircNEK6 serves as a competing endogenous RNA of CCND1 by absorbing miR-503, which might be treated as a novel and potential target for PDAC treatment.

Circ_0070203 Promotes Epithelial-mesenchymal Transition in Ovarian Serous Cystadenocarcinoma through miR-370-3p/TGFβR2 Axis

INTRODUCTION

Circular RNAs (circRNAs) are important biological molecules associated with the pathogenesis of multiple cancers.

OBJECTIVE

This work aimed to investigate the function and molecular mechanism of circ_0070203 in high-grade serous ovarian cystadenocarcinoma (HGSOC).

METHODS

circRNA microarray was conducted to detect the circ_0070203 expression in HGSOC tissues. Bioinformatics analysis was used to find the binding sites between circ_0070203, miR- 370-3p and TGFβR2. Real-time quantitative reverse transcription PCR (RT-qPCR) was executed to detect the expressions of circ_0070203, miR-370-3p and TGFβR2 in HGSOC tissues and SKOV3 cells. Dual-luciferase reporter gene assay was used to validate the relationships between miR-370-3p and circ_0070203 or TGFβR2. Besides, transwell assays were conducted to assess the migrative, invasive abilities of ovarian cancer (OC) cells. Western blotting was adopted to detect the expression of epithelial-mesenchymal transition (EMT)-related proteins. The related patents were also studied during the research.

RESULTS

Circ_0070203 and TGFβR2 were upregulated, while miR-370-3p was downregulated in FIGO stage III-IV HGSOC tissues and SKOV-3 cell lines. circ_0070203 overexpression changed the expression of other EMT-related proteins and enhanced the migrative, invasive abilities of OC cells, while silencing circ_0070203 worked oppositely. Mechanistically, circ_0070203 could upregulate TGFβR2 expression in OC cells via sponging miR-370-3p.

CONCLUSION

Circ_0070203 could promote the epithelial-mesenchymal transition, invasion, and metastasis of HGSOC via regulating the miR-370-3p/TGFβR2 axis. Our findings provided a potential biomarker for HGSOC therapy.

Exosome-transmitted hsa_circ_0012634 suppresses pancreatic ductal adenocarcinoma progression through regulating miR-147b/HIPK2 axis

Circular RNA (circRNA) has been confirmed to play a vital role in pancreatic ductal adenocarcinoma (PDAC) progression. However, the function and regulatory mechanism of hsa_circ_0012634 in PDAC progression remain unclear. Quantitative real-time PCR was used to measure the expression of hsa_circ_0012634, microRNA (miR)-147b and homeodomain interacting protein kinase 2 (HIPK2). Cell function was assessed by cell counting kit 8 assay, EdU assay, colony formation assay and flow cytometry. Glucose uptake and lactate production were evaluated to determine cell glycolysis ability. Protein expression was examined by western blot analysis. RNA interaction was confirmed by RNA pull-down assay and dual-luciferase reporter assay. Exosomes were isolated from serums and cell culture supernatant using ultracentrifugation and identified by transmission electron microscopy. Animal experiments were conducted using nude mice. Hsa_circ_0012634 was downregulated in PDAC tissues and cells, and its overexpression suppressed PDAC cell proliferation, glycolysis and enhanced apoptosis. MiR-147b was targeted by hsa_circ_0012634, and its inhibitors repressed PDAC cell growth and glycolysis. HIPK2 could be targeted by miR-147b, and hsa_circ_0012634 regulated miR-147b/HIPK2 to suppress PDAC cell progression. Hsa_circ_0012634 was lowly expressed in serum exosomes of PDAC patients. Exosomal hsa_circ_0012634 inhibited PDAC cell growth and glycolysis in vitro, as well as tumorigenesis in vivo. Exosomal hsa_circ_0012634 restrained PDAC progression via the miR-147b/HIPK2 pathway, confirming that hsa_circ_0012634 might serve as a diagnosis and treatment biomarker for PDAC.

hsa_circ_0002980 prevents proliferation, migration, invasion, and epithelial-mesenchymal transition of liver cancer cells through microRNA-1303/cell adhesion molecule 2 axis

BACKGROUND

Liver cancer (LC) is a rare malignancy. Circular RNA (circRNA) dysregulation is associated with LC metastasis. hsa_circ_0002980 was found to be unexpectedly downregulated in LC tissues; however, its specific function remains unclear.

METHODS

hsa_circ_0002980 expression was confirmed using RT-qPCR. The effects of circ_0002980 on the proliferation, metastasis, and EMT-related proteins of LC cells were assessed using clone formation, flow cytometry, Transwell assays, and Western blotting. The relationship between circ_0002980 and miR-1303 or miR-1303 and CADM2 was analyzed using a dual-luciferase reporter assay. Thereafter, the influence of these three genes on LC cell progression was determined through rescue experiments.

RESULTS

hsa_circ_0002980 expression was lower in LC. circ_0002980 overexpression inhibited the proliferation, migration, invasion, and EMT of LC cells. In addition, circ_0002980 specifically binds to miR-1303, and the accelerated effect of miR-1303 overexpression on LC progression was partially reversed by circ_0002980. Moreover, miR-1303 can also target CADM2, and CADM2-mediated prevention can also be attenuated by miR-1303 overexpression.

CONCLUSIONS

In LC cells, circ_0002980 upregulation prevents cell proliferation, metastasis, and EMT by affecting the miR-1303/CADM2 axis. Therefore, this axis may be a novel therapeutic target in LC.

CircSOD2 polarizes macrophages towards the M1 phenotype to alleviate cisplatin resistance in gastric cancer cells by targeting the miR-1296/STAT1 axis

Cisplatin is the first-line drug for gastric cancer (GC). Cisplatin resistance is the most important cause of poor prognosis for GC. Increasing evidence has identified the important role of macrophage polarization in chemoresistance. CircRNAs are newly discovered non-coding RNAs, characterized by covalently closed loops with high stability. Previous studies have reported a significant difference between circRNA profiles expressed in classically activated M1 macrophages, and those expressed in alternatively activated M2 macrophages. However, the underlying mechanism behind the regulation of GC cisplatin resistance by macrophages remains unclear. In our study, we observed the aberrant high expression of circSOD2 in M1 macrophages derived from THP-1. These expression patterns were confirmed in macrophages from patients with GC. Detection of the M1 and M2 markers confirmed that overexpression of circSOD2 enhances M1 polarization. The viability of cisplatin-treated GC cells was significantly reduced in the presence of macrophages overexpressing circSOD2, and cisplatin-induced apoptosis increased dramatically. In vivo experiments showed that macrophages expressing circSOD2 enhanced the effect of cisplatin. Moreover, we demonstrated that circSOD2 acts as a microRNA sponge for miR-1296 and regulates the expression of its target gene STAT1 (signal transducer and activator of transcription 1). CircSOD2 exerts its function through the miR-1296/STAT1 axis. Inhibition of circSOD2/miR-1296/STAT1 may therefore reduce M1 polarization. Overexpression of circSOD2 promotes the polarization of M1 macrophages and enhances the effect of cisplatin in GC. CircSOD2 is a novel positive regulator of M1 macrophages and may serve as a potential target for GC chemotherapy.

CeRNA regulates network and expression and SNP effect on NFKBIA of cashmere fineness

In this study, a total of 1140 Liaoning Cashmere Goats (LCG) were genotyped for single nucleotide polymorphism (SNP) of NFKBIA gene. There are 15 SNPs and 7 genotypes have been found, and G1547A (GG) genotype has been associated with cashmere fineness and cashmere yield. An integrated ceRNA regulatory network of NFKBIA gene was made. To prove NFKBIA and these non-coding RNAs (ncRNAs) may be related to cashmere fineness, we performed qPCR on these ncRNA in LCG coarse type skin (CT-LCG) and LCG fine type skin (FT-LCG). The result of qPCR showed lncRNA XLOC_011060 and ciRNA452 are at high expression level in CT-LCG, all miRNAs appear high expressed in FT-LCG, and mir-93 was the most significant difference between CT-LCG and FT-LCG. In addition, five miRNAs were selected for qPCR in different genotypes. The qPCR results showed that mir-93 might negatively regulate cashmere fineness and mir-17-5p may play a positive role in regulating cashmere fineness of individuals with G1355A (AG) genotype. These results demonstrated that NFKBIA gene is associated with cashmere fineness of LCG and G1547A (GG) genotype is the preferred marker genotype for cashmere fineness.

circDENND4C, a novel serum marker for epithelial ovarian cancer, acts as a tumor suppressor by downregulating miR-200b/c

RESEARCH OBJECTIVE

To explore the diagnostic value of circ-DENN domain containing 4 C (circDENND4C) in epithelial ovarian cancer (EOC) and the corresponding mechanism.

METHODS

We determined the expression of circDENND4C and miR-200b/c in tissues and serum specimens as well as EOC cell lines using qRT-PCR. Basic clinical data, and serum HE4 and CAl25 levels were acquired from patients' clinical records. Expression-related correlations and the diagnostic value of serum circDENND4C in EOC were also estimated. CCK-8 and flow cytometry were performed to detect the effect of circDENND4C on cell proliferation and apoptosis.

RESULTS

circDENND4C level was lowest while miR-200b/c was highest in EOC tissues, followed by benign and normal tissues. Similarly, serum circDENND4C was lowest while miR-200b/c was highest in EOC patients. Moreover, serum circDENND4C was lower in patients with benign ovarian tumors than in healthy women, while miR-200b/c expression was higher. circDENND4C was negatively associated with miR-200b/c in EOC tissues and serum specimens, and serum circDENND4C was also negatively correlated with serum HE4 and CAl25 in EOC patients. circDENND4C expression in both tissue and serum was negatively related to FIGO and TNM stage, and tumor size in EOC. Serum circDENND4C could distinguish healthy persons from patients with benign ovarian tumors and EOC, and they showed a higher specificity and accuracy than serum CA125 or HE4 in EOC diagnosis. circDENND4C upregulation significantly suppressed EOC cell proliferation and facilitated apoptosis by downregulating miR-200b/c in vitro.

CONCLUSIONS

Summarily, circDENND4C acts as a tumor inhibitor by downregulating miR-200b/c in EOC and could be a possible tumor marker for EOC diagnosis.KEY MESSAGEScircDENND4C expression was lowest while miR-200b/c was highest in EOC tissues or serums, followed by benign and normal tissues or serums.circDENND4C was involved in malignant progression of EOC, concretely, overexpression of circDENND4C suppressed EOC cell proliferation and stimulated apoptosis via downregulating miR-200b/c, and circDENND4C expression in both tissue and serum was closely related to FIGO and TNM stages and tumor size in EOC.Serum circDENND4C showed a higher specificity and accuracy than serum CA125 or HE4 in EOC diagnosis.HIGHLIGHTScircDENND4C expression was lowest while miR-200b/c was highest in EOC tissues, followed by benign and normal tissues.Serum circDENND4C was lowest while miR-200b/c was highest in EOC patients, followed by benign patients and healthy women.Overexpression of circDENND4C suppresses EOC cell proliferation and stimulates apoptosis via downregulating miR-200b/c.circDENND4C expression in both tissue and serum was closely related to FIGO and TNM stage and tumor size in EOC.Serum circDENND4C showed a higher specificity and accuracy than serum CA125 or HE4 in EOC diagnosis.

Dual effects of circRNA in thyroid and breast cancer

CircRNA, the latest research hotspot in the field of RNA, is a special non-coding RNA molecule, which is unable to encode proteins and bind polyribosomes. As a regulatory molecule, circRNA participates in cancer cell generation and progression mainly through the mechanism of competitive endogenous RNA. In numerous regulated cancer organs, the thyroid and breast are both endocrine organs, and both are regulated by the hypothalamic pituitary gland axis. Thyroid cancer (TC) and breast cancer (BC) are both sexually prevalent in women and both are affected by hormones, thus they are intrinsically linked. In addition, recent epidemiological surveys have found that, early metastasis and recurrence of breast cancer remain the main cause of survival in breast cancer patients. Although at home and abroad, studies have shown that new targeted anti-tumor drugs with numerous tumor markers are gradually being used in the clinic, evidence for potential molecular mechanisms affecting its prognosis lacks clinical studies. Therefore, we search the relevant literature, and based on the latest domestic and international consensus, review the molecular mechanisms and regulation relevance of circRNA, compare the difference of the same circRNA in two tumors, to more deeply understand and lay the foundation for future clinical diagnostic, therapeutic and prognostic studies in large samples.

High-throughput analysis of CircRNA in cows with naturally infected Staphylococcus aureus mammary gland

Circular RNAs (CircRNA) are a special type of non-coding RNA molecule with a closed ring structure and are not affected by RNA exonucases. It has stable expression, is not easy to degrade, and exists in most eukaryotes. However, circRNA regulation of cow mastitis has not been widely recognized. Mammary epithelial tissues were collected from healthy Holstein cows (HCN) and mastitis Holstein cows (HCU). RNA sequencing (RNA SEQ) was performed for the differentially expressed circRNAs, and analysis results showed that 19 differentially expressed circRNAs were identified in HCN and HCU, among which 6 circRNAs were up-regulated and 13 circRNAs were down-regulated. We randomly selected nine circRNAs for Q-PCR verification, and the results showed consistent expression. Three circRNAs: circRNA2860, circRNA5323 and circRNA4027 were confirmed to be significantly differentially expressed circRNAs in cow mastitis. Also, their host genes TRPS1, SLC12A2 and MYH11 might be directly or indirectly play a role in cow mastitis. Furthermore, RNA polymerase transcription factor binding and tight junction are most enriched in GO and KEGG pathways, respectively. In addition, the regulatory network of circRNA-miRNA has been inferred from a bioinformatics perspective, which may help to understand the underlying molecular mechanism of circRNAs involved in regulating mastitis in cows.

CircFLNA/miR-214 modulates regulatory T cells by regulating PD-1 in acute lung injury induced by sepsis

Sepsis-induced acute respiratory distress syndrome (ARDS) remains a major complication of death from bacterial infection. Regulatory T cells (Tregs) are important regulators in addressing lung injury. Considering the extensive research of circular RNAs (circRNAs), the role of circRNA in Treg modulation during ARDS remains unclear. In this study, patients with sepsis-induced ARDS along with non-ARDS controls were obtained, and bronchoalveolar lavage fluid (BALF) was collected as clinical samples. Additionally, cecal ligation and puncture (CLP) was performed to construct a septic ARDS model, and lung tissues as well as peripheral blood were collected. mRNA expressions were measured by RT-qPCR. ELISA was carried out to measure the concentration of inflammatory factors. A combination of online bioinformatics, dual-luciferase reporter, and RND pull-down assays was performed to verify interactions between microRNA (miRNA) and circRNA/mRNA. Tregs were measured by flow cytometry. Our data suggested that circFLNA was aberrantly elevated in ARDS, and depletion of circFLNA upregulated CD4+CD25+Foxp3+ Tregs and decreased inflammatory response. Additionally, miR-214-5p which binds with circFLNA, reversed circFLNA-induced effects in ARDS. Programmed cell death protein 1 (PD-1) is a downstream target gene of miR-214-5p, and abrogated the effects of miR-214-5p on regulating CD4+CD25+Foxp3+ Tregs and inflammatory response. In a word, circFLNA/miR-214-5p/PD-1 signaling is a novel pathway that modulates Tregs in ARDS.

CircMMP11 as a prognostic biomarker mediates miR-361-3p/HMGB1 axis to accelerate malignant progression of hepatocellular carcinoma

As a high metastatic tumor, patients having hepatocellular carcinoma (HCC) show poor prognosis. The carcinogenic roles of circMMP11 are generally described in the development of other cancers. However, there is a lack of studies on its involvement in HCC. Therefore, we investigated the potential role and molecular mechanisms of CircMMP11 in the development of HCC in vitro, providing preliminary evidence for the clinical treatment of HCC. First, we examined the expression of CircMMP11 in HCC tissues and cell lines in both clinical and in vitro experiments. We then used a loss-of-function assay to determine CircMMP11's regulatory role on the malignant characteristics of HCC cells. The results showed that high expression of CircMMP11 in HCC was associated with patient overall survival. Serum CircMMP11 had good diagnostic efficacy in distinguishing HCC patients from the control group. In vitro, inhibiting CircMMP11 suppressed the malignant characteristics of human HCC cell lines by directly sequestering miR-361-3p, which further affected the downstream gene HMGB1 expression. In addition, we knocked down CircMMP11 and found that its deletion inhibited the malignant characteristics of HCC cells through the miR-361-3p/HMGB1 axis.

Macrophage microvesicle-derived circ_YTHDF2 in methamphetamine-induced chronic lung injury

Long-term abuse of methamphetamine (MA) can cause lung toxicity. Intercellular communication between macrophages and alveolar epithelial cells (AECs) is critical for maintaining lung homeostasis. Microvesicles (MVs) are an important medium of intercellular communication. However, the mechanism of macrophage MVs (MMVs) in MA-induced chronic lung injury remains unclear. This study aimed to investigate if MA can augment the activity of MMVs and if circ_YTHDF2 is a key factor in MMV-mediated macrophage-AEC communication, and to explore the mechanism of MMV-derived circ_YTHDF2 in MA-induced chronic lung injury. MA elevated peak velocity of the pulmonary artery and pulmonary artery accelerate time, reduced the number of alveolar sacs, thickened the alveolar septum, and accelerated the release of MMVs and the uptake of MMVs by AECs. Circ_YTHDF2 was downregulated in lung and MMVs induced by MA. The immune factors in MMVs were increased by si-circ_YTHDF. Circ_YTHDF2 knockdown in MMVs induced inflammation and remodelling in the internalised AECs by MMVs, which was reversed by circ_YTHDF2 overexpression in MMVs. Circ_YTHDF2 bound specifically to and sponged miRNA-145-5p. Runt-related transcription factor 3 (RUNX3) was identified as potential target of miR-145-5p. RUNX3 targeted zinc finger E-box-binding homeobox 1 (ZEB1)-related inflammation and EMT of AECs. In vivo, circ_YTHDF2 overexpression-MMVs attenuated MA-induced lung inflammation and remodelling by the circ_YTHDF2-miRNA-145-5p-RUNX3 axis. Therefore, MA abuse can induce pulmonary dysfunction and alveolus injury. The immunoactivity of MMVs is regulated by circ_YTHDF2. Circ_YTHDF2 in MMVs is the key to communication between macrophages and AECs. Circ_YTHDF2 sponges miR-145-5p targeting RUNX3 to participate in ZEB1-related inflammation and remodelling of AECs. MMV-derived circ_YTHDF2 would be an important therapeutic target for MA-induced chronic lung injury. KEY POINTS: Methamphetamine (MA) abuse induces pulmonary dysfunction and alveoli injury. The immunoactivity of macrophage microvesicles (MMVs) is regulated by circ_YTHDF2. Circ_YTHDF2 in MMVs is the key to MMV-mediated intercellular communication between macrophages and alveolar epithelial cells. Circ_YTHDF2 sponges miR-145-5p targeting runt-related transcription factor 3 (RUNX3) to participate in zinc finger E-box-binding homeobox 1 (ZEB1)-related inflammation and remodelling. MMV-derived circ_YTHDF2 would be an important therapeutic target for MA-induced chronic lung injury.