OBJECTIVES: To explore the mechanism of Circ-MYOCD back-splicing and its regulatory role in myocardial hypertrophy. METHODS: Sanger sequencing and RNase R assays were performed to verify the circularity and stability of Circ-MYOCD, whose subcellular distribution was determined by nuclear-cytoplasmic fractionation. Bioinformatics analysis and mass spectrometry from pull-down assays were conducted to predict the RNA-binding proteins (RBPs) interacting with Circ-MYOCD. In rat cardiomyocytes H9C2 cells, the effects of HNRNPH1 and HNRNPL knockdown and overexpression on Circ-MYOCD back-splicing were evaluated. In a H9C2 cell model of angiotensin II (Ang II)-induced myocardial hypertrophy, the expression of HNRNPH1 was detected, the effects of HNRNPH1 knockdown and overexpression on progression of myocardial hypertrophy were assessed, and the regulatory effect of HNRNPH1 on Circ-MYOCD back-splicing was analyzed. RESULTS: Sanger sequencing confirmed that the junction primers could amplify the correct Circ-MYOCD sequence. RNase R and nuclear-cytoplasmic fractionation assays showed that Circ-MYOCD was stable and predominantly localized in the cytoplasm. Bioinformatics analysis and mass spectrometry from the Circ-MYOCD pull-down assay identified HNRNPH1 and HNRNPL as the RBPs interacting with Circ-MYOCD. In H9C2 cells, HNRNPH1 knockdown significantly enhanced while its overexpression inhibited Circ-MYOCD back-splicing; HNRNPH1 overexpression obviously increased the expressions of myocardial hypertrophy markers ANP and BNP, while its knockdown produced the opposite effect. In Ang II-induced H9C2 cells, which exhibited a significant increase of HNRNPH1 expression and increased expressions of ANP and BNP, HNRNPH1 knockdown obviously increased Circ-MYOCD expression, decreased MYOCD expression and lowered both ANP and BNP expressions. CONCLUSIONS HNRNPH1 regulates Circ-MYOCD back-splicing to influence the progression of myocardial hypertrophy.
Animals ; Rats ; RNA, Circular/genetics* ; Cardiomegaly/metabolism* ; Myocytes, Cardiac/metabolism* ; Heterogeneous-Nuclear Ribonucleoprotein Group F-H/metabolism* ; Cell Line ; RNA Splicing ; Angiotensin II ; RNA-Binding Proteins

OBJECTIVES: To investigate the mechanism by which circ_EPHB4 regulates temozolomide (TMZ) sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis. METHODS: We detected the expression levels of circ_EPHB4, miR-424-5p and Wnt3 mRNA in glioma specimens from 25 patients with primary glioma and 25 patients experiencing relapse following temozolomide-based chemotherapy and in TMZ-sensitive and -resistant glioma A172 and SHG44 cells with circ_EPHB4 knockdown using qRT-PCR, and Wnt3 protein expression level was detected with Western blotting. Cell viability, colony-forming ability, and apoptosis of the cells with circ_EPHB4 knockdown were assessed, and the targeted regulation relationship between circ_EPHB4, miR-424-5p, and Wnt3 was verified by dual luciferase reporter assay and RNA immunoprecipitation (RIP) experiments. The effect of circ_EPHB4 knockdown on tumorigenesis of glioma cells was evaluated in subcutaneous tumor-bearing nude mouse models. RESULTS: The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes (P=0.014). In TMZ-resistant glioma cells, circ_EPHB4 knockdown resulted in an obvious reduction of IC50 value of TMZ, inhibited cell colony formation, and promoted cell apoptosis, and these effects were reversed by miR-424-5p knockdown. The expressions of miR-424-5p and circ_EPHB4 were negatively correlated in glioma tissues (P=0.011). MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA, P-gp, MRP1 and bax. CONCLUSIONS Circ_EPHB4 regulates Wnt3 expression through "sponge adsorption" of miR-424-5p, thereby modulating TMZ-resistant glioblastoma cell clonogenesis, apoptosis, and TMZ sensitivity, suggesting the potential of circ_EPHB4 as a therapeutic target for reversing drug resistance of gliomas.
MicroRNAs/genetics* ; Humans ; Temozolomide ; Glioma/genetics* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Wnt3 Protein/metabolism* ; Mice ; Apoptosis ; RNA, Circular ; Drug Resistance, Neoplasm ; Brain Neoplasms/pathology* ; Signal Transduction

OBJECTIVES: To investigate the role of circular RNA circ_0000437 in regulating biological behaviors of breast cancer cells and the molecular mechanism. METHODS: Breast cancer MCF-7 and MDA-MB-231 cells were transfected with sh-circ_0000437, mimics, inhibitor, si-CTPS1, or their respective negative controls. qRT-PCR was used to detect the expression levels of circ_0000437, let-7b-5p, CTPS1, Notch1, Hes1, and Numb in breast cancer cell lines and tissues. RNase R digestion was used to confirm the circular structure of circ_0000437 and its subcellular localization in the breast cancer cells was determined by cellular distribution analysis. The changes in proliferation, invasion and migration of the transfected cells were assessed using CCK-8 assay, Transwell assay and scratch assay. Dual-luciferase reporter gene and RNA immunoprecipitation assays were employed to validate binding interactions among circ_0000437, let-7b-5p, and CTPS1. The cellular expressions of CTPS1, E-cadherin, N-cadherin, and vimentin proteins were detected with Western blotting. A tumor-bearing mouse model was used to verify the oncogenic mechanism of circ_0000437 and CTPS1. RESULTS: Circ_0000437 and CTPS1 were upregulated while let-7b-5p was downregulated in breast cancer tissues and cell lines. Circ_0000437 or CTPS1 knockdown obviously suppressed breast cancer cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT). Overexpression of let-7b-5p produced similar inhibitory effects, whereas inhibition of let-7b-5p significantly enhanced malignant behaviors of the cells. In the tumor-bearing mouse models, circ_0000437 knockdown significantly suppressed tumor growth, but co-transfection of the cells with pcDNA-CTPS1 accelerated tumor growth. Binding sites were identified between circ_0000437 and let-7b-5p and between let-7b-5p and CTPS1, and circ_0000437, let-7b-5p, and CTPS1 showed functional interactions in breast cancer cells. CONCLUSIONS Circ_0000437 is upregulated in breast cancer tissues and cells, and its high expression promotes proliferation, invasion, migration and EMT of breast cancer cells through the let-7b-5p/CTPS1 axis.
Humans ; Epithelial-Mesenchymal Transition ; Cell Proliferation ; MicroRNAs/metabolism* ; RNA, Circular ; Breast Neoplasms/metabolism* ; Cell Movement ; Female ; Neoplasm Invasiveness ; Cell Line, Tumor ; MCF-7 Cells ; Animals ; Mice

OBJECTIVES: To analyze the differential expression and biological functions of circRNAs in the anterior lens capsules of high myopic patients with cataract and their pathogenic roles in the development of this condition. METHODS: Anterior lens capsule specimens were collected intraoperatively from 36 patients with age-related cataract (ARC) and 36 high myopic patients with cataract. Among these, 18 specimens from each group were selected for whole transcriptome sequencing and biological analysis, and the remaining 36 specimens were used for validation of circPDGFRA, circFOXJ3, hsa_circ_0004767, hsa_circ_0007528, ciCRIM1, circMAN1A2, circSLC5A3, and circPTK2 expressions using RT-qPCR. hsa_circ_0007528 was selected for cell experiments to examine its effects on proliferation, migration, and apoptosis of lens epithelial cells (LECs). RESULTS: A total of 16 192 circRNAs were detected in the specimens from both groups, among which 62 circRNAs were differentially expressed (29 upregulated and 33 downregulated). GO and KEGG analyses revealed that the differentially expressed circRNAs were primarily localized in the cytoplasm, nucleoplasm, and endoplasmic reticulum, and were involved in signaling pathways associated with Gap junction and the PI3K-Akt, NF-κB, Jak-STAT, HIF-1, and MAPK signaling pathways. The ceRNA network predicted multiple target genes. RT-qPCR validation results were consistent with the sequencing data. In the LECs, upregulation of hsa_circ_0007528 significantly inhibited cell proliferation and migration and obviously promoted cell apoptosis. CONCLUSIONS The expression profile of circRNAs in the anterior lens capsule of high myopic patients with cataract differs from that of ARC patients. Upregulation of hsa_circ_0007528 inhibits LEC proliferation and migration and promotes cell apoptosis.
Humans ; Cataract/complications* ; RNA, Circular ; Myopia/genetics* ; Apoptosis ; Cell Proliferation ; Epithelial Cells ; Cell Movement ; Anterior Capsule of the Lens/metabolism* ; Male ; Female

OBJECTIVES: To investigate the oncogenic role of circular RNA circ_EPHB4 in glioma and its molecular mechanism. METHODS: Microarray analysis was performed to identify the differentially expressed circRNAs in glioma tissues. The effects of circ_EPHB4 on glioma cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and tumorigenicity in vivo were assessed using scratch wound healing assay, Transwell invasion assay and nude mouse models bearing subcutaneous tumors. RNA immunoprecipitation (RIP), RNA stability assays, and gene overexpression and silencing techniques were employed to validate the synergistic regulatory effect of circ_EPHB4 and the N6-methyladenosine (m⁶A) reader protein YTHDF3 on Wnt3 expression. RESULTS: Circ_EPHB4 was significantly overexpressed by 2.3 folds (|log2FC|=1.2, P<0.01) in glioma tissues compared to the adjacent tissues, and by 2.5 folds in glioma cell line U373 compared to normal cells (P<0.001). Overexpression of circ_EPHB4 significantly enhanced migration and invasion of glioma cells, and promoted the expressions of EMT markers N-cadherin and vimentin. In the tumor-bearing mouse models, the tumor volume in circ_EPHB4 overexpression group was significantly greater than that in the control group, and the lung metastatic foci increased by 4.2 folds. Overexpression of circ_EPHB4 promoted oncogenesis by upregulating Wnt3 expression, while YTHDF3 extended the half-life of Wnt3 mRNA in an m⁶A-dependent manner. Simultaneous knockdown of circ_EPHB4 and YTHDF3 resulted in an obvious reduction of Wnt3 mRNA expression by up to 47% compared to its level following knocking down either circ_EPHB4 or YTHDF3 alone. CONCLUSIONS Circ_EPHB4 and YTHDF3 promote glioma progression by jointly targeting the Wnt3 signaling pathway, which may provide a new therapeutic strategy for gliomas.
Glioma/genetics* ; Humans ; Animals ; Cell Line, Tumor ; RNA-Binding Proteins/genetics* ; RNA, Circular ; Epithelial-Mesenchymal Transition ; Mice, Nude ; Cell Movement ; Wnt3 Protein/genetics* ; Mice ; Disease Progression ; Adenosine/metabolism* ; Brain Neoplasms/metabolism* ; Gene Expression Regulation, Neoplastic

OBJECTIVES: To explore the expression profile of circular RNAs (circRNAs) and their potential roles in prognosis and progression of Wilms' tumor (WT). METHODS: Four pairs of WT and adjacent tissues were collected for high-throughput circRNA sequencing to identify the differentially expressed circular RNAs. RT-qPCR was used to verify the expression levels of the top 6 candidate circRNAs in the clinical samples. hsa_circ_0001900 was selected for analysis of its correlation with clinicopathological features and prognosis in 34 patients with WT. Sanger sequencing and RNase R digestion experiments were used to verify the cycling site and structural stability of hsa_circ_0001900 molecule. RESULTS: A total of 23 978 circular RNA molecules were identified in WT tissues by high-throughput circular RNA sequencing, and among them 614 were differentially expressed in WT. hsa_circ_0001900 showed the highest expression level among the differentially expressed circRNAs, which was consistent with the findings in clinical tumor samples and the sequencing results. Correlation analysis showed that hsa_circ_0001900 expression level was positively correlated with WT volume, and the children with high hsa_circ_0001900 expression had a lowered recurrence-free survival rate. The results of Sanger sequencing verified the circular splice site sequence of the molecule, and Rnase R digestion assay confirmed its stable covalent structure. CONCLUSIONS This study presents a comprehensive expression profile of circular RNAs in WT, and the expression level of hsa_circ_0001900 is related to the size of WT and the patients' prognosis, suggesting its possible role as a key driving gene in WT progression.
Humans ; RNA, Circular ; Wilms Tumor/pathology* ; Prognosis ; High-Throughput Nucleotide Sequencing ; Kidney Neoplasms/genetics* ; Sequence Analysis, RNA ; Male ; Female

OBJECTIVE: To investigate the relationship between peripheral blood circular RNA Bardet-Biedl syndrome 9 (circBBS9) and circRNA catenin beta 1 (circCTNNB1) and weaning failure of mechanical ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: A prospective, observational cohort study was conducted. The patients with AECOPD who received invasive mechanical ventilation and passed the spontaneous breathing test (SBT) admitted to the First Affiliated Hospital of Hebei North University from January 2022 to February 2024 were selected as the study subjects. According to the outcome of weaning, the patients were divided into failed weaning group and successful weaning group. At admission and before SBT, the expression levels of circBBS9 and circCTNNB1 in peripheral blood were detected by fluorescence quantitative polymerase chain reaction (PCR). General information, acute physiology and chronic health evaluation II (APACHEII) score within 24 hours of admission, vital signs before SBT and the most recent laboratory indicators before SBT of the patients were collected. The differences in circBBS9 and circCTNNB1 expression levels and clinical data between the two groups were compared. Multivariate Logistic regression was used to analyze the influencing factors of the weaning failure. Receiver operator characteristic curve (ROC curve) was used to analyze the predictive value of each index on weaning failure. RESULTS: Ultimately, 132 patients with AECOPD who underwent invasive mechanical ventilation and passed the SBT were enrolled in the study. Among them, 82 patients were successfully weaned from mechanical ventilation, while 50 patients failed to be weaned, resulting in a weaning failure rate of 37.88%. There was no statistically significant difference in the expression levels of circBBS9 and circCTNNB1 in the peripheral blood at admission of patients between the two groups. The expression level of circBBS9 in the peripheral blood before SBT of patients in the failed weaning group was significantly higher than that in the successful weaning group (2^-ΔΔCt: 131.64±30.24 vs. 100.00±21.32), and the expression level of circCTNNB1 was significantly lower than that in the successful weaning group (2^-ΔΔCt: 79.90±16.82 vs. 100.00±26.43), and the differences were statistically significant (both P < 0.05). The APACHEII score within 24 hours of admission and the levels of RSBI, SCr, and PCT before SBT in the failed weaning group were significantly higher than those in the successful weaning group [APACHEII score: 22.54±4.62 vs. 16.56±4.58, RSBI: 81.90±16.56 vs. 63.25±17.00, SCr (μmol/L): 100.20±17.27 vs. 89.93±26.29, PCT (μg/L): 1.08±0.18 vs. 0.87±0.22], and the Alb level before SBT was significantly lower than that in the successful weaning group (g/L: 29.71±2.73 vs. 33.93±2.89), and the differences were statistically significant (all P < 0.05). There was no statistically significant difference in other clinical data between the two groups. Multivariate Logistic regression analysis showed that circBBS9 [odds ratio (OR) = 1.291, 95% confidence interval (95%CI) was 1.049-1.588] and APACHEII score (OR = 2.897, 95%CI was 1.004-8.353), RSBI (OR = 1.413, 95%CI was 1.057-1.890) were independent risk factors for weaning failure (all P < 0.05), and circCTNNB1 (OR = 0.812, 95%CI was 0.688-0.959) and Alb (OR = 0.149, 95%CI was 0.036-0.614) were protective factors (both P < 0.05). ROC curve analysis showed that circBBS9, circCTNNB1, APACHEII score, RSBI, and Alb all had certain value for predicting weaning failure. The area under the ROC curve (AUC) and 95%CI were 0.820 (0.750-0.890), 0.755 (0.674-0.835), 0.827 (0.757-0.897), 0.795 (0.715-0.876), and 0.854 (0.791-0.919), respectively. Using the multivariate Logistic regression equation as the combined indicator, the AUC for predicting weaning failure reached 0.997 (95%CI was 0.993-1.000), which was significantly higher than that of the single indicators including circBBS9, circCTNNB1, APACHEII score, RSBI, and Alb (the Z value was 5.582, 6.093, 5.771, 5.932, and 5.182, respectively, all P < 0.05). CONCLUSIONS High expression of circBBS9 and low expression of circCTNNB1 in the peripheral blood of AECOPD patients receiving invasive mechanical ventilation before SBT are associated with weaning failure. circBBS9, circCTNNB1 combined with APACHEII score, RSBI and Alb are helpful for predicting the failure of weaning in these patients.
Humans ; Pulmonary Disease, Chronic Obstructive/blood* ; Prospective Studies ; Ventilator Weaning ; RNA, Circular/blood* ; Respiration, Artificial ; Male ; Female ; Aged

This study investigated the specific immune response of BALB/c mice that was induced by a circular RNA (circRNA) vaccine expressing the herpes simplex virus type II (HSV-2) glycoprotein D (gD). The aim was to evaluate the immunological potential of this vaccine and lay a foundation for developing an mRNA vaccine against HSV-2. PCR and homologous recombination were employed to integrate the gD gene obtained from the pT7AMP-gD ectodomain plasmid into pUC57 to generate the recombinant plasmid pUC57-circ-gD, which was then sequenced and characterized. In vitro transcription and cyclization were performed on the template DNA to generate pUC57-circ-gD mRNA. To validate the formation of circular RNA, we cleaved the pUC57-circ-gD mRNA with RNase R and employed RT-PCR to validate the cyclization. The pUC57-circ-gD mRNA was then transfected into 293T cells. After 72 h, the cell supernatant was collected, and Western blotting was employed to measure the protein level of gD. Subsequently, the mRNA was encapsulated in lipid nanoparticles (LNPs) by microfluidic encapsulation. BALB/c mice were administrated with the encapsulated mRNA, and blood was collected from the fundus venous plexus after 21 and 35 days, and from the enucleated eyeballs after 49 days. Enzyme-linked immunosorbent assay was employed to measure the titers of antibodies, including virus-neutralizing antibodies. After 49 days, spleens were harvested and assessed for secretion of interferon-gamma (IFN-γ) by solid-phase enzyme-linked immunospot. The results showed successful construction and sequencing of the recombinant plasmid. RNase R digestion confirmed the presence of circular RNAs. Western blotting of the 293T cells transfected with the mRNA showed clear specific bands. The quality of the vaccine was tested by size exclusion chromatography-high performance liquid chromatography, which showed that the purity of the vaccine was about 90%. The mRNA-LNP showcased the particle size of 82.76 nm and an encapsulation rate of approximately 98%. Following three-dose vaccination, all immunized mice exhibited steady weight gain with 100% survival rate throughout the 28-day observation period, indicating no significant acute toxicity associated with the vaccine formulation. The immunized mice showed dose-dependent increases in serum IgG antibody titer and IFN-γ secretion by splenocytes and they were resistant to virus attacks. These findings indicate good immunogenicity and persistence of the pUC57-circ-gD mRNA vaccine, providing a reference for further studies on circRNA vaccines.
Animals ; Mice, Inbred BALB C ; RNA, Circular ; Mice ; Humans ; Herpesvirus 2, Human/genetics* ; Viral Envelope Proteins/genetics* ; Antibodies, Viral/blood* ; HEK293 Cells ; Female ; Nanoparticles ; Plasmids

OBJECTIVE: To observe the effects of moxibustion at "Feishu" (BL13) and "Xinshu" (BL15) on the circular RNA of exon 2-5 of the Pan3 gene (circPAN3), forkhead box O3 (FOXO3), and Bcl-2/adenovirus E1B19kDa-interacting protein 3 (BNIP3) in rats with chronic heart failure (CHF), and explore the potential mechanisms of moxibustion in alleviating myocardial fibrosis. METHODS: Ten rats of 60 male SPF-grade SD rats were randomly assigned into a normal group. The remaining rats underwent left anterior descending coronary artery (LAD) ligation to establish the CHF model. Forty successfully modeled rats were randomly divided into a model group, a moxibustion group, a rapamycin (RAPA) group, and a moxibustion+RAPA group, with 10 rats in each group. The moxibustion group received mild moxibustion at bilateral "Feishu" (BL13) and "Xinshu" (BL15), 30 min per session. The RAPA group received intraperitoneal injection of the autophagy activator RAPA (1 mg/kg). The moxibustion+RAPA group first received RAPA injection, followed by mild moxibustion at bilateral "Feishu" (BL13) and "Xinshu" (BL15). All interventions were administered once daily for 4 consecutive weeks. After the intervention, cardiac ultrasound was used to measure ejection fraction (EF) and left ventricular fractional shortening (FS). Serum placental growth factor (PLGF) level was determined by ELISA. Myocardial tissue morphology and collagen volume were assessed using hematoxylin-eosin (HE) staining and Masson's trichrome staining. The expression levels of circPAN3, FOXO3, and BNIP3 mRNA in myocardial tissue were detected by real-time PCR, while FOXO3 and BNIP3 protein expression levels were analyzed by Western blot. RESULTS: Compared with the normal group, the model group exhibited myocardial cell disorder, severe fibrosis, and increased collagen volume (P<0.01), along with significantly decreased EF, FS, and circPAN3 mRNA expression in myocardial tissue (P<0.01), and the serum PLGF level, as well as FOXO3 and BNIP3 mRNA and protein expression in myocardial tissue were increased (P<0.01). Compared with the model group, the moxibustion group showed reduced myocardial fibrosis, decreased collagen volume (P<0.01), increased EF, FS, and circPAN3 mRNA expression in myocardial tissue (P<0.01), and decreased serum PLGF level as well as FOXO3 and BNIP3 mRNA and protein expression in myocardial tissue (P<0.01). Compared with the model group, the RAPA group showed further deterioration in these parameters (P<0.01). Compared with the RAPA group, the moxibustion+RAPA group exhibited alleviation of myocardial fibrosis, reduced collagen volume (P<0.01), increased EF, FS, and circPAN3 mRNA expression in myocardial tissue (P<0.01), and decreased serum PLGF level as well as FOXO3 and BNIP3 mRNA and protein expression in myocardial tissue (P<0.01). CONCLUSION Moxibustion could alleviate myocardial fibrosis in CHF rats, possibly through upregulation of myocardial circPAN3 expression, downregulation of FOXO3 and BNIP3 expression, and inhibition of excessive myocardial autophagy.
Animals ; Moxibustion ; Heart Failure/metabolism* ; Male ; Rats ; Rats, Sprague-Dawley ; Myocardium/pathology* ; RNA, Circular/metabolism* ; Membrane Proteins/metabolism* ; Forkhead Box Protein O3/metabolism* ; Acupuncture Points ; Humans ; Fibrosis/genetics* ; Chronic Disease/therapy* ; Mitochondrial Proteins

Esophageal squamous cell carcinoma (ESCC) is a prevalent malignancy of the digestive tract that poses a significant threat to human health, with an incidence rate that continues to rise globally. Increasing research highlights the crucial role of non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in regulating ferroptosis and contributing to the malignant progression of ESCC. These ncRNAs influence the proliferation, apoptosis, and invasion capabilities of ESCC cells by modulating iron metabolism and redox balance. miRNAs can regulate cellular iron accumulation and oxidative stress by targeting ferroptosis-related genes; lncRNAs may indirectly affect iron metabolic pathways by competitively binding to miRNAs; circRNAs, through a sponge effect, may regulate the activity of miRNAs. This review systematically summarizes the mechanisms of ncRNAs-mediated regulation of ferroptosis in ESCC, focusing on molecular mechanisms, regulatory networks, and their specific roles in the ferroptosis process. Additionally, the potential of ncRNAs in ESCC diagnosis, prognosis assessment, and therapeutic intervention is discussed, aiming to provide new insights and targets for ferroptosis-based tumor therapy.
Ferroptosis/genetics* ; Humans ; Esophageal Neoplasms/physiopathology* ; Esophageal Squamous Cell Carcinoma ; MicroRNAs/physiology* ; RNA, Long Noncoding/physiology* ; RNA, Circular ; RNA, Untranslated/physiology*