NFE2L2 and insomnia: Ramelteon, which is used for treating insomnia clinically, protects neuronal degeneration in traumatic brain injury (TBI) through promoting nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation, leading to the increasing of downstream factors of NRF2, including SOD-1, heme oxygenase-1, and NQO1 (Wang et al., 2019).