Oxidative Stress Induced by Arsenite is Involved in YTHDF2 Phase Separation

Abstract

YTH N⁶-methyladenosine RNA binding protein 2 (YTHDF2) undergoes phase separation in response to the stimulation of high concentration of arsenite, suggesting that oxidative stress, the major mechanism of arsenite toxicity, may play a role in YTHDF2 phase separation. However, whether arsenite-induced oxidative stress is involved in phase separation of YTHDF2 has yet to be established. To explore the effect of arsenite-induced oxidative stress on YTHDF2 phase separation, the levels of oxidative stress, YTHDF2 phase separation, and N⁶-methyladenosine (m⁶A) in human keratinocytes were detected after exposure to various concentrations of sodium arsenite (0-500 µM; 1 h) and antioxidant N-acetylcysteine (0-10 mM; 2 h). We found that arsenite promoted oxidative stress and YTHDF2 phase separation in a concentration-dependent manner. In contrast, pretreatment with N-acetylcysteine significantly relieved arsenate-induced oxidative stress and inhibited YTHDF2 phase separation. As one of the key factors to YTHDF2 phase separation, N⁶-methyladenosine (m⁶A) levels in human keratinocytes were significantly increased after arsenite exposure, accompanied by upregulation of m⁶A methylesterase levels and downregulation of m⁶A demethylases levels. On the contrary, N-acetylcysteine mitigated the arsenite-induced increase of m⁶A and m⁶A methylesterase and the arsenite-induced decrease in m⁶A demethylase. Collectively, our study firstly revealed that oxidative stress induced by arsenite plays an important role in YTHDF2 phase separation driven by m⁶A modification, which provides new insights into the arsenite toxicity from the phase-separation perspective.

Keywords: Arsenite; N6-methyladenosine; Oxidative stress; Phase separation.