NFE2L2 and obesity due to melanocortin 4 receptor deficiency: In particular, there is a need to further explore the involvement of PPARγ and Nrf2 signaling pathways because these were found to play dual roles in obesity demonstrating both anti-obesity and obesity-promoting effects (Zhang et al., 2015[150]; Ma et al., 2018[81]; Bayliak and Abrat, 2020[9]).