Deoxynivalenol induces m6A-mediated upregulation of p21 and growth arrest of mouse hippocampal neuron cells in vitro

Abstract Hippocampal neurons maintain the ability of proliferation throughout life to support neurogenesis. Deoxynivalenol (DON) is a mycotoxin that exhibits brain toxicity, yet whether and how DON affects hippocampal neurogenesis remains unknown. Here, we use mouse hippocampal neuron cells (HT-22) as a model to illustrate the effects of DON on neuron proliferation and to explore underlying mechanisms. DON exposure significantly inhibits the proliferation of HT-22 cells, which is associated with an up-regulation of cell cycle inhibitor p21 at both mRNA and protein levels. Global and site-specific m 6 A methylation levels on the 3’UTR of p21 mRNA are significantly increased in response to DON treatment, whereas inhibition of m 6 A hypermethylation significantly alleviates DON-induced cell cycle arrest. Further mechanistic studies indicate that the m 6 A readers YTHDF1 and IGF2BP1 are responsible for m 6 A-mediated increase in p21 mRNA stability. Meanwhile, 3’UTR of E3 ubiquitin ligase TRIM21 mRNA is also m 6 A hypermethylated, and another m 6 A reader YTHDF2 binds to the m 6 A sites, leading to decreased TRIM21 mRNA stability. Consequently, TRIM21 suppression impairs ubiquitin-mediated p21 protein degradation. Taken together, m 6 A-mediated upregulation of p21, at both post-transcriptional and post-translational levels, contributes to DON-induced inhibition of hippocampal neuron proliferation. These results may provide new insights for epigenetic therapy of neurodegenerative diseases. Graphical abstract DON inhibits the proliferation of HT-22 cells. RNA m 6 A hypermethylation on the transcript of p21 enhances the mRNA stability in a YTHDF1- and IGF2BP1-dependent manner, which leads to the upregulation of p21. RNA m 6 A hypermethylation on the transcript of TRIM21 decreases the mRNA stability in a YTHDF2-dependent manner, which contributes to prevent p21 ubiquitin-mediated degradation. High expression of p21 contributes to inhibit cell proliferation.