MAP2K4 and Parkinson disease: Furthermore, ADEVs enriched with miR-200a-3p prevent cell death in 1-methyl-4-phenylpyridinium (MPP+)-treated SH-SY5Y cells and glutamate-treated hippocampal neurons through down-regulation of mitogen-activated protein kinase kinase 4 (MKK4), reinforcing its role in mitigating neurotoxicity in in vitro PD models [82].