NR4A2 and brain ischemia: In the present study, we therefore sought to determine: (1) how Nurr1 level and Nurr1-related microRNAs change in the brain of MCAO/R rats, an in vivo model; (2) in in vitro studies, what are the post-transcriptional regulatory network of Nurr1 and the specific mechanisms of Nurr1 on microglia activation; (3) in an in vivo study, whether miR-145-5p/Nurr1/TNF-α signal exerts neuron injury function upon cerebral ischemia-reperfusion in rats.