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

Circular RNA (circRNA) is a novel class of single-stranded RNAs with a closed loop structure. The majority of circRNAs are formed by a back-splicing process in pre-mRNA splicing. Their expression is dynamically regulated and shows spatiotemporal patterns among cell types, tissues and developmental stages. CircRNAs have important biological functions in many physiological processes, and their aberrant expression is implicated in many human diseases. Due to their high stability, circRNAs are becoming promising biomarkers in many human diseases, such as cardiovascular diseases, autoimmune diseases and human cancers. In this review, we focus on the translational potential of using human blood circRNAs as liquid biopsy biomarkers for human diseases. We highlight their abundant expression, essential biological functions and significant correlations to human diseases in various components of peripheral blood, including whole blood, blood cells and extracellular vesicles. In addition, we summarize the current knowledge of blood circRNA biomarkers for disease diagnosis or prognosis.
Autoimmune Diseases/blood* ; Biomarkers, Tumor/blood* ; Cardiovascular Diseases/blood* ; Humans ; Liquid Biopsy ; Neoplasms/blood* ; RNA, Circular/blood* ; RNA, Neoplasm/blood*