METTL3 modulates bone Cancer pain via m6A-dependent JAK2/STAT3 activation in spinal astrocytes.

N6-methyladenosine (m6A) is primarily associated with extensive changes in epigenetic regulation in eukaryotic organisms, particularly facilitated by the Methyltransferase-like 3 (METTL3) enzyme in cancer and inflammatory pain. However, the pathways through which METTL3 mediates these conditions remain largely unknown. This study elucidates the pathways by which m6A methylation of JAK2 mRNA by METTL3 occurs within astrocytes in the spinal cord, thereby facilitating continuous JAK2 mRNA translation. In bone cancer pain (BCP) mice, the upregulation of TNF-α and IL-1β aggravates pain sensation. Furthermore, the levels of METTL3 and m6A in the spinal cord increase as bone cancer pain progresses, with METTL3 co-localizing with activated astrocytes. The findings revealed that silencing METTL3 minimized changes in JAK2 mRNA levels while maintaining consistent m6A-installed STAT3 mRNA. Importantly, METTL3 knockdown specifically decreased the m6A modification level of Jak2. Pharmacological inhibition of m6A using STM2457 significantly decreased m6A levels and JAK2/p-JAK2 expression, are consistent with the results of knockdown experiments. Additionally, the expression of JAK2/STAT3, the activation of astrocytes, and inflammatory mediators in the spinal cord were significantly decreased following METTL3-shRNA intervention. Pain responses in mice were ameliorated, as indicated by increased paw withdrawal mechanical threshold (PWMT) and reduced spontaneous flinches (NSF). These findings demonstrate the essential role of METTL3 in initiating bone cancer pain (BCP) by promoting astrocyte-mediated neuroinflammation and activating the JAK2/STAT3 signaling pathway. Therefore, the application of METTL3 in BCP treatment emerges as a novel potential remedy in clinical settings.