Methyltransferase-like protein 16 suppresses spinal cord injury by regulating microglia polarization via N6-methyladenosine-modified downregulation of MCEMP1.

Abstract

N6-methyladenosine (m6A) modification is a prevalent epigenetic mechanism influencing spinal cord injury (SCI) progression. Methyltransferase-like protein 16 (METTL16) plays crucial roles in various diseases. However, its specific function and mechanism in SCI remain undefined. After establishment of an SCI model mice, pathological alterations in spinal cord tissue were assessed using hematoxylin and eosin, Nissl, and TUNEL staining. Datasets from Gene Expression Omnibus were acquired to identify METTL16-regulated core target genes, MCEMP1, associated with SCI. Methylation sites in MCEMP1 were predicted using the SRAMP database, and METTL16 m6A modification of MCEMP1 by METTL16 was validated utilizing methylated RNA immunoprecipitation and RNA pull-down. mRNA levels of METTL16 and MCEMP1 were quantified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blot was used to assess protein expression of METTL16, MCEMP1, polarization markers, and apoptosis proteins. Inflammatory cytokine secretion was measured via enzyme-linked immunosorbent assay (ELISA). Neuronal apoptosis in mouse BV2-hippocampal neuron cocultures was evaluated using flow cytometry. The results showed that METTL16 was downregulated in SC tissue following SCI. MCEMP1 suppression resulted from METTL16-mediated m6A methylation modification of MCEMP1. METTL16 promoted M2 polarization of microglia in vitro and inhibited neuronal apoptosis by repressing MCEMP1 expression, thereby mitigating SCI.