Objective To investigate the m6A modification of nuclear receptor NR4A2 (Nuclear Receptor Subfamily 4, Group A, Member 2) mRNA by METTL3 and its mechanism of action in microglial M1 polarization and neuroinflammation in Parkinson's disease (PD). Methods A PD mouse model was established by unilateral medial forebrain bundle (MFB) injection of 6-hydroxydopamine (6-OHDA). Motor function was evaluated by apomorphine-induced rotation test, rotarod test, and pole test. Immunofluorescence, HE staining, and Western blot were used to detect dopaminergic neuron damage in the substantia nigra, expression of inflammatory factors, and related molecules. ELISA was employed to measure the global m⁶A modification level in tissues. An in vitro inflammatory model was constructed by stimulating BV2 microglia with lipopolysaccharide (LPS). METTL3 was knocked down or overexpressed using siRNA and overexpression plasmids, respectively. RNA immunoprecipitation (RIP) was used to verify the binding of METTL3 to NR4A2 mRNA, with binding sites predicted by SRAMP. The effect of METTL3 on NR4A2 mRNA stability was assessed using the actinomycin D assay. Results Compared with the control group, PD model mice exhibited impaired motor function, nuclear pyknosis in the substantia nigra, and a reduced number of tyrosine hydroxylase (TH)-positive neurons (P<0.05). Expression of M1 phenotype markers (IL-1β, iNOS, TNF-α), global m⁶A modification levels, and METTL3 expression were increased, while NR4A2 expression was decreased (P<0.05), consistent trends were observed in the LPS-stimulated BV2 cells. In the METTL3 knockdown group, expression of M1 phenotype markers decreased and NR4A2 mRNA half-life was shortened (P<0.05). RIP confirmed that METTL3 directly binds to NR4A2 mRNA (P<0.05), with potential binding sites predicted by SRAMP. In the METTL3 overexpression group, expression of M1 phenotype markers increased and NR4A2 mRNA stability was extended (P<0.05). Conclusions METTL3-mediated m⁶A modification of NR4A2 plays a crucial pro-inflammatory role in PD by regulating microglial M1 polarization.
Key words
NR4A2; /
/
Parkinson's disease; /
/
Neuroinflammation; /
/
m6A RNA methylation; /
/
METTL3
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] Ye H, Robak LA, Yu M, et al. Genetics and Pathogenesis of Parkinson's Syndrome[J]. Annu Rev Pathol, 2023, 18:95-121. DOI:10.1146/annurev-pathmechdis-031521-034145.
[2] Tansey MG, Wallings RL, Houser MC, et al. Inflammation and immune dysfunction in Parkinson disease[J]. Nat Rev Immunol, 2022, 22(11):657-673. DOI:10.1038/s41577-022-00684-6.
[3] Yildirim-Balatan C, Fenyi A, Besnault P, et al. Parkinson's disease-derived α-synuclein assemblies combined with chronic-type inflammatory cues promote a neurotoxic microglial phenotype[J]. J Neuroinflammation, 2024, 21(1): 54. DOI:10.1186/s12974-024-03043-5.
[4] Kwon HS, Koh SH. Neuroinflammation in neurodegenerative disorders: the roles of microglia and astrocytes[J]. Transl Neurodegener, 2020, 9(1):42. DOI:10.1186/s40035-020-00221-2.
[5] Yu H, Chang Q, Sun T, et al. Metabolic reprogramming and polarization of microglia in Parkinson's disease: Role of inflammasome and iron[J]. Ageing Res Rev, 2023, 90:102032. DOI:10.1016/j.arr.2023.102032.
[6] Liang Z, Liu W, Cao M, et al. Epigenetic regulation-mediated disorders in dopamine transporter endocytosis: A novel mechanism for the pathogenesis of Parkinson's disease[J]. Theranostics, 2025, 15(6):2250-2278. DOI:10.7150/thno.107436.
[7] Qi Z, Wang S, Li J, et al. Protective role of mRNA demethylase FTO on axon guidance molecules of nigro-striatal projection system in manganese-induced parkinsonism[J]. J Hazard Mater, 2022, 426:128099. DOI: 10.1016/j.jhazmat.2021.128099.
[8] Yin H, Ju Z, Zheng M, et al. Loss of the m6A methyltransferase METTL3 in monocyte-derived macrophages ameliorates Alzheimer's disease pathology in mice[J]. PLoS Biol, 2023, 21(3):e3002017. DOI: 10.1371/journal.pbio.3002017.
[9] Zhao F, Xu Y, Gao S, et al. METTL3-dependent RNA m6A dysregulation contributes to neurodegeneration in Alzheimer's disease through aberrant cell cycle events[J]. Mol Neurodegener, 2021, 16(1):70. DOI:10.1186/s13024-021-00484-x.
[10]Wu X, Liu H, Wang J, et al. The m6A methyltransferase METTL3 drives neuroinflammation and neurotoxicity through stabilizing BATF mRNA in microglia[J]. Cell Death Differ, 2025, 32(1):100-117. DOI:10.1038/s41418-024-01329-y.
[11]Jakaria M, Haque ME, Cho DY, et al. Molecular Insights into NR4A2(Nurr1): an Emerging Target for Neuroprotective Therapy Against Neuroinflammation and Neuronal Cell Death[J]. Mol Neurobiol, 2019, 56(8):5799-5814. DOI:10.1007/s12035-019-1487-4.
[12]He Y, Wang Y, Yu H, et al. Protective effect of Nr4a2 (Nurr1) against LPS-induced depressive-like behaviors via regulating activity of microglia and CamkII neurons in anterior cingulate cortex[J]. Pharmacol Res, 2023, 191:106717.DOI: 10.1016/j.phrs.2023.106717.
[13]吴悦, 卢丽娣, 卿涛, 等. 不同剂量6-OHDA对小鼠多巴胺能神经元及行为的影响[J].中国病理生理杂志, 2024, 40(11):2005-2013.DOI: 10.3969/j.issn.1000-4718.2024.11.003.
Wu Y, Lu LD, Qing T, et al. Effects of Different Doses of 6-OHDA on Dopaminergic Neurons and Behaviors in Mice [J]. Chinese Journal of Pathophysiology, 2024, 40(11): 2005-2013. DOI: 10.3969/j.issn.1000-4718.2024.11.003.
[14]Nam HY, Nam JH, Yoon G, et al. Ibrutinib suppresses LPS-induced neuroinflammatory responses in BV2 microglial cells and wild-type mice[J]. J Neuroinflammation, 2018, 15(1):271. DOI:10.1186/s12974-018-1308-0.
[15]Wang Y, Liao X, Guo Q, et al. Dual-pathway targeted therapy for Parkinson's disease: Biomimetic nanosomes inhibit ferroptosis and pyroptosis through NLRP3 inflammasome regulation[J]. Bioact Mater, 2025, 51:825-840. DOI:10.1016/j.bioactmat.2025.06.033.
[16]Zheng R, Yan Y, Dai S, et al. ASC specks exacerbate α‑synuclein pathology via amplifying NLRP3 inflammasome activities[J]. J Neuroinflammation, 2023, 20(1):26. DOI:10.1186/s12974-023-02709-w.
[17]Guo X, Qiu W, Li B, et al. Hypoxia-Induced Neuronal Activity in Glioma Patients Polarizes Microglia by Potentiating RNA m6A Demethylation[J]. Clin Cancer Res, 2024, 30(6):1160-1174. DOI: 10.1158/1078-0432.CCR-23-0430.
[18]Zhang N, Lin R, Gao W, et al. Curcumin Modulates PTPRZ1 Activity and RNA m6A Modifications in Neuroinflammation-Associated Microglial Response[J]. Adv Sci (Weinh), 2025, 12(15): e2405263. DOI:10.1002/advs.202405263.
[19]Hu L, Si L, Dai X, et al. Exosomal miR-409-3p secreted from activated mast cells promotes microglial migration, activation and neuroinflammation by targeting Nr4a2 to activate the NF-κB pathway[J]. J Neuroinflammation, 2021, 18(1):68. DOI:10.1186/s12974-021-02110-5.
[20]Tao Y, Zhang Y, Jin X, et al. Epigenetic regulation of beta-endorphin synthesis in hypothalamic arcuate nucleus neurons modulates neuropathic pain in a rodent pain model[J]. Nat Commun, 2023, 14(1):7234. DOI:10.1038/s41467-023-43022-7.
[21]Slobodin B, Bahat A, Sehrawat U, et al. Transcription Dynamics Regulate Poly(A) Tails and Expression of the RNA Degradation Machinery to Balance mRNA Levels[J]. Mol Cell, 2020, 78(3):434-444. DOI: 10.1016/j.molcel.2020.03.022.
[22]Mao Y, Meng Y, Zou K, et al. Advanced paternal age exacerbates neuroinflammation in offspring via m6A modification-mediated intergenerational inheritance[J]. J Neuroinflammation, 2024, 21(1):249. DOI:10.1186/s12974-024-03248-8.
[23]Ding L, Wu H, Wang Y, et al. m6A Reader Igf2bp1 Regulates the Inflammatory Responses of Microglia by Stabilizing Gbp11 and Cp mRNAs[J]. Front Immunol, 2022,13:872252. DOI:10.3389/fimmu. 2022. 872252.
[24]Huang H, Weng H, Sun W, et al. Recognition of RNA N6-methyladenosine by IGF2BP proteins enhances mRNA stability and translation[J]. Nat Cell Biol, 2018, 20(3):285-295. DOI:10.1038/s41556-018-0045-z.
[25]Lv JY, Xing LJ, Zhong X, et al. Role of N6-methyladenosine modification in central nervous system diseases and related therapeutic agents[J]. Biomed Pharmacother, 2023, 162:114583. DOI:10.1016/j.biopha.2023.114583.
[26]Zaccara S, Jaffrey SR. A Unified Model for the Function of YTHDF Proteins in Regulating m6A-Modified mRNA[J]. Cell, 2020, 181(7):1582-1595.e18. DOI: 10.1016/j.cell.2020.05.012.
PDF(5764 KB)
