METTL14-mediated N6-methyladenosine RNA Modification Regulates Survival And Function Of Dopaminergic Neurons

Parkinson’s disease(PD)is a neurodegenerative disease characterized by progressive loss of dopaminergic neurons in the substantia nigra,which usually occurs in people aged over 60.Relevant studies indicate that PD is associated with multiple factors such as environment,age,genetics and relative elements.Further research focus on exploring the pathogenesis of PD will facilitate the development of clinical treatment against this disease.N6-methyladenosine(m6A)modification is a chemical modification occurring in eukaryotic m RNA,which exists in all cellular types in the central nervous system(CNS).The m6 A modification is mainly regulated by two groups of proteins called the“writers” and “erasers”.The m6 A writers catalyze the methylation modification of the sixth nitrogen atom of adenylate,while the erasers are responsible for the demethylation process.The m6 A readers recognize and bind to the RNA modification site which lead to diffenrent RNA processings such as m RNA splicing,translation,nuclear retention and stability.The whole process achieves the purpose of regulating the protein expression and their biological functions.In recent years,the key role of m6 A modification in the CNS has been gradually revealed.Studies have indicated that the m6 A writer protein METTL14 impacts the midbrain associated motor function in mice by changing the m6 A level in striatal D1R/D2 R neurons;And studies have also revealed that decrease of m6 A level leads to dopaminergic neuronal loss in vitro.However,whether METTL14 protein directly affect the survival of dopaminergic neurons and its relative functions in the substantia nigra by changing the level of m6 A is unclear and remains to be explored.In our study,we used the METTL14 conditional knockout mice to construct METTL14 knockout model specific in the substantia nigra region.We explored the effect of m6 A writer METTL14 on dopaminergic neuron-mediated motor function in the mice.Our in vitro study also explored the effect of METTL14 on the survival of dopaminergic neuronal cell line SH-SY5 Y cells by knocking down the METTL14 expression using crisper-cas9 techniques.Our resrults demonstrated that the deletion of METTL14 in the SNpc region of mice resulted in a significant decrease of the motor function of the mice,while overexpression of METTL14 by lentivirus in that region could improve the motor ability of the mice.The in vitro experiment results showed that deletion of METTL14 cause accumulation of the mitochondrial ROS.The SH-SY5 Y cells was not able to effectively scavenge the generated ROS,which lead to cellular death.Our study indicated that m6 A modification mediated by METTL14 is critical to the survival of dopaminergic neurons.Overall,our study provide a new insights for further exploration of the novel pathogenic mechanisms of PD characterized by dopaminergic neuronal loss.