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

Abstract

AbstractHippocampal 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 m6A methylation levels on the 3’UTR of p21 mRNA are significantly increased in response to DON treatment, whereas inhibition of m6A hypermethylation significantly alleviates DON-induced cell cycle arrest. Further mechanistic studies indicate that the m6A readers YTHDF1 and IGF2BP1 are responsible for m6A-mediated increase in p21 mRNA stability. Meanwhile, 3’UTR of E3 ubiquitin ligase TRIM21 mRNA is also m6A hypermethylated, and another m6A reader YTHDF2 binds to the m6A sites, leading to decreased TRIM21 mRNA stability. Consequently, TRIM21 suppression impairs ubiquitin-mediated p21 protein degradation. Taken together, m6A-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 m6A 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 m6A 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.