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Updated: Jul 6, 2025
Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury
Published on: September 4, 2013
METTL3 promotes microglial inflammation via MEF2C in spinal cord injury
Dongliang Wang1, Wei Qian2, Duanrong Wu3
1Department of Spinal Surgery, Yancheng First People's Hospital, Yancheng, 224006, China.
Abstract:
Spinal cord injury (SCI) is a significant contributor to disability in contemporary society, resulting in substantial psychological and economic burdens for patients and their family. Microglia-mediated inflammation is an important factor affecting the nerve repair of SCI patients. N6-methyladenosine (m6A) is a prevalent epigenetic modification in mammals, which shows a strong association with inflammation. However, the mechanism of m6A modification regulating microglia-mediated inflammation is still unclear. Here, we observed that METTL3, a m6A methylase, was increased in SCI mice and lipopolysaccharide (LPS)-exposed BV2 cells. Knockdown of METTL3 inhibited the increased expression of iNOS and IL-1β induced by LPS in vitro. Subsequently, MEF2C, myocyte-specific enhancer factor 2C, was decreased in SCI mice and LPS-exposed BV2 cells. Knockdown of MEF2C promoted the expression of iNOS and IL-1β. Sequence analysis showed that there were multiple highly confident m6A modification sites on the MEF2C mRNA. METTL3 antibody could pull down a higher level of MEF2C mRNA than the IgG in RNA binding protein immunoprecipitation assay. Knockdown of METTL3 promoted MEF2C protein expression and MEF2C mRNA expression, accompanied by a reduced m6A modification level on the MEF2C mRNA. Knockdown of MEF2C inhibited the anti-inflammatory effect of METTL3 siRNA. Our results suggest that METTL3 promotes microglia inflammation via regulating MEF2C mRNA m6A modification induced by SCI and LPS treatment.
Insights
Spinal cord injury (SCI) triggers inflammation. METTL3 promotes this inflammation by regulating m6A modification of MEF2C mRNA in microglia, hindering nerve repair.
Area of Science:
- Neuroscience
- Epigenetics
- Immunology
Background:
- Spinal cord injury (SCI) causes significant disability and burdens.
- Microglia-mediated inflammation is a key factor hindering nerve repair after SCI.
- N6-methyladenosine (m6A) modification is linked to inflammation, but its role in SCI-induced microglia inflammation is unclear.
Purpose of the Study:
- To investigate the mechanism of m6A modification in regulating microglia-mediated inflammation following SCI.
- To explore the role of METTL3 and MEF2C in SCI-induced neuroinflammation.
Main Methods:
- Used SCI mouse models and lipopolysaccharide (LPS)-exposed BV2 microglia cells.
- Investigated the expression of METTL3, MEF2C, iNOS, and IL-1β.
- Performed knockdown experiments for METTL3 and MEF2C.
- Utilized RNA binding protein immunoprecipitation (RIP) assay to detect m6A modification on MEF2C mRNA.
Main Results:
- METTL3 expression increased in SCI mice and LPS-treated BV2 cells.
- Knockdown of METTL3 reduced LPS-induced iNOS and IL-1β expression.
- MEF2C expression decreased in SCI mice and LPS-treated BV2 cells.
- METTL3 directly binds to MEF2C mRNA, regulating its m6A modification, protein, and mRNA expression.
- METTL3 knockdown promoted MEF2C expression and reduced m6A modification on MEF2C mRNA.
- MEF2C knockdown abolished the anti-inflammatory effect of METTL3 knockdown.
Conclusions:
- METTL3 promotes microglia-mediated inflammation in SCI by regulating m6A modification of MEF2C mRNA.
- This pathway represents a potential therapeutic target for SCI-related neuroinflammation.
