NR4A2 and Parkinson disease: On the other hand, nuclear receptor-related 1 protein (NURR1) expression, a transcription factor important in dopaminergic neuron homeostasis and regulation of neuroinflammation, was significantly downregulated in peripheral blood mononuclear cells of PD patients alongside the upregulation of several cytokines (TNFa, IL1b, IL6, and IL10) [599].