METTL3 Mediates Epithelial–Mesenchymal Transition by Modulating FOXO1 mRNA N⁶‐Methyladenosine‐Dependent YTHDF2 Binding: A Novel Mechanism of Radiation‐Induced Lung Injury

Abstract

The biological roles of epithelial–mesenchymal transition (EMT) in the pathogenesis of radiation‐induced lung injury (RILI) have been widely demonstrated, but the mechanisms involved have been incompletely elucidated. N6‐methyladenosine (m6A) modification, the most abundant reversible methylation modification in eukaryotic mRNAs, plays vital roles in multiple biological processes. Whether and how m6A modification participates in ionizing radiation (IR)‐induced EMT and RILI remain unclear. Here, significantly increased m6A levels upon IR‐induced EMT are detected both in vivo and in vitro. Furthermore, upregulated methyltransferase‐like 3 (METTL3) expression and downregulated α‐ketoglutarate‐dependent dioxygenase AlkB homolog 5 (ALKBH5) expression are detected. In addition, blocking METTL3‐mediated m6A modification suppresses IR‐induced EMT both in vivo and in vitro. Mechanistically, forkhead box O1 (FOXO1) is identified as a key target of METTL3 by a methylated RNA immunoprecipitation (MeRIP) assay. FOXO1 expression is downregulated by METTL3‐mediated mRNA m6A modification in a YTH‐domain family 2 (YTHDF2)‐dependent manner, which subsequently activates the AKT and ERK signaling pathways. Overall, the present study shows that IR‐responsive METTL3 is involved in IR‐induced EMT, probably by activating the AKT and ERK signaling pathways via YTHDF2‐dependent FOXO1 m6A modification, which may be a novel mechanism involved in the occurrence and development of RILI.

Identification of related-genes of T cells in lung tissue of chronic obstructive pulmonary disease based on bioinformatics and experimental validation

“…FOXO1, a member of the Forkead transcription factor family, regulatescell stability, and the cell cycle and coordinates the response to various environmental changes 36 , 37 . There is evidence suggesting that FOXO1protein expression levels are increased in the quadriceps muscle of COPD patients with muscleatrophy 38 – 41 .…”

The mir-199b-5p encapsulated in adipocyte-derived exosomes mediates radioresistance of colorectal cancer cells by targeting JAG1

“…Subsequent determination of protein concentrations in the lysates was conducted using the BCA Protein Assay kit (Beyotime, China). Specific steps for the Western blot experiment were conducted in accordance with the protocols outlined in our previously published article [ 15 ]. After chemiluminescence, the target bands and the internal reference (GAPDH or α-Tubulin) were quantified by Image J software.…”

RNA N6-Methyladenosine Modification in DNA Damage Response and Cancer Radiotherapy

“…M6A modification may also be involved in radiation-induced lung injury (RILI). A recent study reported that after irradiation of lung tissue, METTL3-YTHDF2 regulates forkhead box O1 (FOXO1) mRNA stability through M6A modification, activating the EPK and AKT signaling pathways, ultimately leading to EMT [ 60 ]. Furthermore, Zhao et al found that Zinc finger and BTB domain-containing protein 7B (Zbtb7b) reduce radiation-induced IL-6 production in the lung by inhibiting M6A modification of IL-6 mRNA and nuclear transport, which provides a new target for the treatment of radiation pneumonitis [ 61 ].…”