NR4A2 and Parkinson disease: Minocycline and doxycycline, two frequently used semisynthetic second-generation tetracycline derivatives, shown potent neuroprotective efficacy in experimental neurodegenerative/neuropsychiatric illnesses with minimal toxicity, for instance, in a PD rat model, minocycline can prevent rotenone-induced neurotoxicity associated with upregulation of Nurr1 (Bortolanza et al., 2018; Sun et al., 2019).