Some of these pro-inflammatory cytokines, TNF-α as well as Toll-like receptors, have been implicated in glucocorticoid-mediated stress response49 and in the etiology of major depression.50 MiR-101a, miR-124, miR-721, miR-181c and miR-365 target ERK/MAPK1, a gene involved in several physiological functions in brain including cell proliferation, differentiation and cell survival. Here, MAPK1 is linked to major depressive disorder.