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[Display omitted] • CircAFF2 is upregulated and miR-488 is downregulated in ICH. • CircAFF2 functions as a competitive endogenous RNA for miR-488. • CLSTN3 is a downstream target of miR-488. • CircAFF2 regulates neuronal cell injury via targeting miR-488 to upregulate CLSTN3. • CircAFF2 silencing reduces ICH injury in mice by miR-488/CLSTN3 axis. Intracerebral hemorrhage (ICH), a subtype of devastating stroke, carries high morbidity and mortality worldwide. CircRNA AFF2 (circAFF2) was significantly increased in ICH patients, but the underlying mechanism of circAFF2 is unknown. Hemin was employed to treat neuronal cells to mimic ICH in vitro. Mice were injected with collagenase VII-S to establish in vivo ICH models. Genes and protein expressions were detected using qRT-PCR and Western blotting. The interaction among circAFF2, miR-488, and CLSTN3 was validated by dual-luciferase reporter assay and RNA-RIP. Cell viability, MDA, iron, GSH, and lipid ROS were examined using the MTT, the commercial kits, and flow cytometry, respectively. ICH injury in mice was evaluated using neurological deficit scores and brain water measurements. CircAFF2 was significantly increased in ICH in vivo and in vitro models. CircAFF2 bound to miR-488 and knockdown of circAFF2 or overexpression of miR-488 inhibited hemin-induced injury of neuronal cells as indicated by increased cell viability and reduced markers of oxidative stress and lipid peroxidation. CLSTN3 was the downstream target of miR-488. Silencing of circAFF2 or miR-488 overexpression reduced CLSTN3 expression and protected against the injury of neuronal cells. In vivo experiments finally confirmed that circAFF2 knockdown attenuated mice ICH injury via the miR-488/CLSTN3 axis. CircAFF2 promotes the injury of neuronal cells and exacerbates ICH via increasing CLSTN3 by sponging miR-488, suggesting that circAFF2 may be a potential therapeutic target for ICH treatment. [ABSTRACT FROM AUTHOR]

Background: Circular RNA (circRNA) and N6‐methyladenosine (m6A) play a critical role in tumour occurrence and development, including colorectal cancer (CRC). However, little is known about the interaction between circRNA and m6A in the radiosensitivity of CRC. Here, we investigated the role of a novel m6A‐regulated circRNA in CRC. Methods: Differentially expressed circRNAs from radiosensitive and radioresistant CRC tissues were screened. Modifications of the selected circRNAs were examined by methylated RNA immunoprecipitation assay. Finally, the selected circRNAs were subjected to radiosensitivity assay. Results: We identified that circAFF2 is closely related to both radiosensitivity and m6A in CRC. CircAFF2 was highly expressed in patients with radiosensitive rectal cancer, and patients with high expression of circAFF2 had a better prognosis. In addition, circAFF2 can enhance the radiosensitivity of CRC cells both in vitro and in vivo. The regulation of circAFF2 involves ALKBH5‐mediated demethylation, followed by its recognition and degradation via YTHDF2. Rescue experiments revealed that circAFF2 could reverse the radiosensitivity induced by ALKBH5 or YTHDF2. Mechanistically, circAFF2 binds with CAND1, promotes the binding of CAND1 to Cullin1 and inhibits its neddylation, subsequently impacting the radiosensitivity of CRC. Conclusion: We identified and characterised circAFF2 as a novel m6A‐modified circRNA and validated the ALKBH5/YTHDF2/circAFF2/Cullin‐NEDD8 axis as a potential radiotherapy target for CRC. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) have been implicated in the pathological regulation of human diseases by acting as microRNA (miRNA) sponges to affect gene expression. CircRNA Fragile Mental Retardation 2 (circ_AFF2) was dysregulated in rheumatoid arthritis (RA), but little is known about its specific function and hidden molecular mechanism in RA. Circ_AFF2, miR-375 and TAK1-binding 2 (TAB2) expression levels were determined through the quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was performed to analyze cell cycle and apoptosis. Cell proliferation detection was conducted by 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The protein levels were measured using western blot. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). RNA pull-down assay was used to select the miRNA target of circ_AFF2. The interaction between miR-375 and circ_AFF2 or TAB2 was analyzed using the dual-luciferase reporter assay. Contrasted to normal samples and fibroblast-like synoviocytes (FLS), circ_AFF2 expression was upregulated in RA blood samples and FLS-RA cells. Cell cycle, proliferation and inflammatory response were blocked while apoptosis was promoted in FLS-RA after the downregulation of circ_AFF2. In addition, circ_AFF2 could interact with miR-375 and the function of circ_AFF2 was achieved by sponging miR-375 in FLS-RA cells. Moreover, TAB2 was a target of miR-375 and miR-375 repressed RA progression by decreasing TAB2 expression in FLS-RA cells. More importantly, circ_AFF2 promoted the expression of TAB2 by targeting miR-375. These findings clarified that circ_AFF2 induced cell progression, inflammatory response in FLS-RA cells via the miR-375/TAB2 axis. Circ_AFF2 could be used as a biomarker in the diagnosis and treatment of RA. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) contain a new class of non-coding RNAs that play an important role in adjusting biological function and gene expression. But the function of circRNAs in gastric cancer remains unclear. In the present research, we explored the functions of circular RNA AFF2(circAFF2, hsa_circ_0001947) in gastric cancer cells and an animal model of gastric cancer., Methods: The expression of circAFF2, microRNA-6894-5p (miR-6894-5p), and Anthrax toxin receptor 1 (ANTXR 1) were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell counting kit 8 (CCK-8) and transwell assays were used to analyze the knockdown effects of circAFF2, miR-6894-5p, and overexpression of ANTXR 1 on cell proliferation, migration, and invasion abilities. Binding interactions between, circAFF2 and miR-6894-5p and between, miR-6894-5p and ANTXR 1 were detected by Dual-luciferase reporter assays. Levels of protein expression were analyzed by Western blotting. Tumor models were established by subcutaneous injection of tumor cells in nude mice., Result: The result showed that circAFF2 expression was significantly increased in gastric cancer cell lines and tissues. The knockdown of circAFF2 dramatically suppressed the cell migration, invasion and proliferation of gastric cancer cells. In vivo studies showed that knockdown of circAFF2 delayed tumor growth. Furthermore, we revealed that circAFF2 functioned as a sponge to absorb miR-6984-5p and elevated the expression of ANTXR 1., Conclusion: CircAFF2 acts as an oncogene in gastric cancer and exerts its effects via miR-6894-5p/ANTXR 1 signaling., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)