While the nuclear receptor PPAR-γ, a critical transcription factor for transforming microglia into a neuroprotective phenotype, alleviating a variety of brain diseases, such as depression, stroke, Alzheimer’s disease, and so on (Pan et al., 2015; Zhao et al., 2016; Xie et al., 2020; Zhang et al., 2020b). The gene discussed is PPARG; the disease is major depressive disorder.