Methyltransferase-like 3 contributes to inflammatory pain by targeting TET1 in YTHDF2-dependent manner

Abstract The methyltransferase-like 3 ( Mettl3 ) is a key component of the large N6-adenosine-methyltransferase complex in mammalian responsible for RNA N6-methyladenosine (m 6 A) modification, which plays an important role in gene post-transcription modulation. Although RNA m 6 A is enriched in mammalian neurons, its regulatory function in nociceptive information processing remains elusive. Here, we reported that Complete Freund's Adjuvant (CFA)-induced inflammatory pain significantly decreased global m 6 A level and m 6 A writer Mettl3 in the spinal cord. Mimicking this decease by knocking down or conditionally deleting spinal Mettl3 elevated the levels of m 6 A in ten-eleven translocation methylcytosine dioxygenases 1 ( Tet1 ) mRNA and TET1 protein in the spinal cord, leading to production of pain hypersensitivity. By contrast, overexpressing Mettl3 reversed a loss of m 6 A in Tet1 mRNA and blocked the CFA-induced increase of TET1 in the spinal cord, resulting in the attenuation of pain behavior. Furthermore, the decreased level of spinal YT521-B homology domain family protein 2 (YTHDF2), an RNA m 6 A reader, stabilized upregulation of spinal TET1 because of the reduction of Tet1 mRNA decay by the binding to m 6 A in Tet1 mRNA in the spinal cord after CFA. This study reveals a novel mechanism for downregulated spinal cord METTL3 coordinating with YTHDF2 contributes to the modulation of inflammatory pain through stabilizing upregulation of TET1 in spinal neurons.