METTL3 improves spinal cord injury-associated locomotor function via SIRT1 m6A modification and regulation of neuronal ferroptosis

Objective: Inhibition of neuronal Ferroptosis is considered crucial for the recovery of locomotor function following spinal cord injury (SCI). We explored the mechanism of methyltransferase-like 3 (METTL3) mediating Sirtuin 1 (SIRT1) N6-methyladenosine (m6A) modification to regulate neuronal Ferroptosis to improve the locomotor function post-SCI.

Methods: SCI rats were treated with short hairpin-METTL3 adenovirus and a Ferroptosis Activator, Erastin. Simultaneously, METTL3 and SIRT1 were knocked down in lipopolysaccharide-induced primary rat spinal cord neurons in vitro. Locomotor function, the extent of SCI, and Ferroptosis were compared in rats. Cell viability and Apoptosis were also assessed. The interaction between METTL3 and SIRT1 mRNA was predicted using the RPISeq database. The m6A modification sites of SIRT1 were predicted using the SRAMP database. The binding between METTL3 and SIRT1, the m6A modification level of SIRT1, and SIRT1 mRNA stability were examined.

Results: METTL3 expression was upregulated in SCI rats. METTL3 knockdown improved the locomotor function, reduced SCI, and inhibited neuronal Ferroptosis, which were partially reversed by Ferroptosis activation. In vitro, METTL3 knockdown suppressed Ferroptosis in spinal cord neurons by regulating SIRT1 m6A modification, an effect that was partially reversed by SIRT1 knockdown.

Conclusion: Knockdown of METTL3 enhances SIRT1 mRNA stability by regulating SIRT1 m6A modification to upregulate SIRT1, thereby suppressing Ferroptosis and improving locomotor function in SCI rats.

Methyltransferase-like 3; N6-methyladenosine modification; ferroptosis; locomotor function; sirtuin 1; spinal cord injury.