Title:METTL14 Regulates the m6A Modification of TRAF6 to Suppress Mitochondrial Dysfunction and Ferroptosis in Dopaminergic Neurons via the cGAS-STING Pathway
Volume: 24
Issue: 12
Author(s): Liang Shao, Fan Hu, Renxu Xu, Hongbing Nie, Hong Zhang and Ping Zhang*
Affiliation:
- Department of Neurology, Jiangxi Provincial People's
Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang 330006, Jiangxi, China
Keywords:
METTL14, TRAF6, cGAS-STING pathway, parkinson's disease, ferroptosis, mitochondrial dysfunction, dopaminergic neurons.
Abstract:
Objectives: The degeneration of dopaminergic (DA) neurons has emerged
as a crucial pathological characteristic in Parkinson’s disease (PD). To enrich the
related knowledge, we aimed to explore the impact of the METTL14-TRAF6-cGASSTING
axis in mitochondrial dysfunction and ferroptosis underlying DA neuron
degeneration.
Methods: 1-methyl-4-phenylpyridinium ion (MPP+) was used to treat DA neuron MN9D
to develop the PD cell models. Afterward, a cell counting kit, flow cytometer, DCFH-DA
fluorescent probe, and Dipyrromethene Boron Difluoride staining were utilized to
measure the cell viability, iron concentration, ROS level, and lipid peroxidation,
respectively. Meanwhile, the mitochondrial ultrastructure, the activity of mitochondrial
respiratory chain complexes, and levels of malondialdehyde and glutathione were
monitored. In addition, reverse transcription-quantitative polymerase chain reaction
and western blot assays were adopted to measure the expression of related genes.
cGAS ubiquitylation and TRAF6 messenger RNA (mRNA) N6-methyladenosine (m6A)
levels, the linkages among METTL14, TRAF6, and the cGAS-STING pathway were
also evaluated.
Results: METTL14 expression was low, and TRAF6 expression was high after MPP+
treatment. In MPP+-treated MN9D cells, METTL14 overexpression reduced ferroptosis,
ROS generation, mitochondrial injury, and oxidative stress (OS) and enhanced
mitochondrial membrane potentials. TRAF6 overexpression had promoting impacts on
mitochondrial dysfunction and ferroptosis in MPP+-treated MN9D cells, which was
reversed by further overexpression of METTL14. Mechanistically, METTL14 facilitated
the m6A methylation of TRAF6 mRNA to down-regulate TRAF6 expression, thus
inactivating the cGAS-STING pathway.
Conclusion: METTL14 down-regulated TRAF6 expression through TRAF6 m6A
methylation to inactivate the cGAS-STING pathway, thereby relieving mitochondrial
dysfunction and ferroptosis in DA neurons.
