Nuclear Receptor Related 1 Protein - Nurr1 and Inflammation

Nurr1 and Inflammation

Research has been conducted on Nurr1’s role in inflammation, and may provide important information in treating disorders caused by dopaminergic neuron disease. Inflammation in the CNS can result from activated microglia (macrophage analogs for the central nervous system) and other pro-inflammatory factors, such as bacterial lipopolysaccharide (LPS). LPS binds to toll-like receptors (TLR), which induces inflammatory gene expression by promoting signal-dependent transcription factors. To determine which cells are dopaminergic, experiments measured the enzyme tyrosine hydroxylase (TH), which is needed for dopamine synthesis. It has been shown that Nurr1 protects dopaminergic neurons from LPS-induced inflammation, by reducing inflammatory gene expression in microglia and astrocytes. When a short hairpin for Nurr1 was expressed in microglia and astrocytes, these cells produced inflammatory mediators, such as TNFa, NO synthase and IL-1β, supporting the conclusion that reduced Nurr1 promotes inflammation and leads to cell death of dopaminergic neurons. Nurr1 interacts with the transcription factor complex NF-κB-p65 on the inflammatory gene promoters. However, Nurr1 is dependent on other factors to be able to participate in these interactions. Nurr1 needs to be sumoylated and its co-regulating factor, glycogen synthase kinase 3, needs to be phosphorylated for these interactions to occur. Sumolyated Nurr1 recruits CoREST, a complex made of several proteins that assembles chromatin-modifying enzymes. The Nurr1/CoREST complex inhibits transcription of inflammatory genes.