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Recent studies have shown that circular RNAs (circRNAs) are decorated with N6-methyladenosine (m 6 A), a co-transcriptional modification known to participate in the regulation of many processes governing linear RNA metabolism. Nevertheless, the activity of this mark on circRNAs is still poorly understood. In order to facilitate the study of m 6 A-dependent regulation of these molecules, we provide protocols that enable circOme-wide detection of m 6 A as well as the perturbation of several components of the m 6 A machinery followed by assays useful to evaluate the impact of their depletion on the production and, when applicable, on the translation of circRNAs. Other modifications exist and can be explored following the same principles., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Circular RNAs (circRNAs), covalently closed RNAs that originate from back-splicing events, participate in the control of several processes, including those that occur in the development of pathological conditions such as cancer. Hereby, we describe circAFF1, a circular RNA overexpressed in alveolar rhabdomyosarcoma. Using RH4 and RH30 cell lines, a classical cell line models for alveolar rhabdomyosarcoma, we demonstrated that circAFF1 is a cytoplasmatic circRNA and its depletion impacts cell homeostasis favouring cell migration through the downregulation of genes involved in cell adhesion pathways. The presented data underline the importance of this circular RNA as a new partial suppressor of the alveolar rhabdomyosarcoma tumour progression and as a putative future therapeutic target.

N6-Methyladenosine (m 6 A) is well-known for controlling different processes of linear RNA metabolism. Conversely, its role in the biogenesis and function of circular RNAs (circRNAs) is still poorly understood. Here, we characterize circRNA expression in the pathological context of rhabdomyosarcoma (RMS), observing a global increase when compared to wild-type myoblasts. For a set of circRNAs, such an increase is due to the raised expression of the m 6 A machinery, which we also find to control the proliferation activity of RMS cells. Furthermore, we identify the RNA helicase DDX5 as a mediator of the back-splicing reaction and as a co-factor of the m 6 A regulatory network. DDX5 and the m 6 A reader YTHDC1 are shown to interact and to promote the production of a common subset of circRNAs in RMS. In line with the observation that YTHDC1/DDX5 depletion reduces RMS proliferation, our results provide proteins and RNA candidates for the study of rhabdomyosarcoma tumorigenicity., (© 2023. The Author(s).)

Background: Fever is a potential side effect of the Covid-19 vaccination. Patients with Brugada syndrome (BrS) have an increased risk of life-threatening arrhythmias when experiencing fever. Prompt treatment with antipyretic drugs is suggested in these patients., Aim of the Study: To evaluate the incidence and management of fever within 48 h from Covid-19 vaccination among BrS patients., Methods: One hundred sixty-three consecutive patients were enrolled in a prospective registry involving five European hospitals with a dedicated inherited disease ambulatory., Results: The mean age was 50 ± 14 years and 121 (75%) patients were male. Prevalence of Brugada electrocardiogram (ECG) pattern type-1, -2, and -3 was 32%, 44%, and 24%, respectively. Twenty-eight (17%) patients had an implantable cardioverter-defibrillator (ICD). Fever occurred in 32 (19%) BrS patients after 16 ± 10 h from vaccination, with a peak of body temperature of 37.9° ± 0.5°. Patients with fever were younger (39 ± 13 vs. 48 ± 13 years, p = .04). No additional differences in terms of sex and cardiovascular risk factors were found between patients with fever and not. Twenty-seven (84%) out of 32 patients experienced mild fever and five (16%) moderate fever. Pharmacological treatment with antipyretic drugs was required in 18 (56%) out of 32 patients and was associated with the resolution of symptoms. No patient required hospital admission and no arrhythmic episode was recorded in patients with ICD within 48 h after vaccination. No induced type 1 BrS ECG pattern and new ECG features were found among patients with moderate fever., Conclusion: Fever is a common side effect in BrS patients after the Covid-19 vaccination. Careful evaluation of body temperature and prompt treatment with antipyretic drugs may be needed., (© 2022 Wiley Periodicals LLC.)

Circular RNAs (circRNAs) are widely expressed in eukaryotes and are regulated in many biological processes. Although several studies indicate their activity as microRNA (miRNA) and protein sponges, little is known about their ability to directly control mRNA homeostasis. We show that the widely expressed circZNF609 directly interacts with several mRNAs and increases their stability and/or translation by favoring the recruitment of the RNA-binding protein ELAVL1. Particularly, the interaction with CKAP5 mRNA, which interestingly overlaps the back-splicing junction, enhances CKAP5 translation, regulating microtubule function in cancer cells and sustaining cell-cycle progression. Finally, we show that circZNF609 downregulation increases the sensitivity of several cancer cell lines to different microtubule-targeting chemotherapeutic drugs and that locked nucleic acid (LNA) protectors against the pairing region on circZNF609 phenocopy such effects. These data set an example of how the small effects tuned by circZNF609/CKAP5 mRNA interaction might have a potent output in tumor growth and drug response., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)