Considering our finding that the ERK1/2 signaling pathway analysis was significantly up-regulated in the CRS-treated mice, as well as literature that activation of the ERK/p38/JNK pathway was involved in the neuroinflammatory regulation of depression (Liu et al., 2018), we focused on ERK/p38/JNK pathway in this study. Here, MAPK8 is linked to major depressive disorder.