For instance, SIRT1 regulates in vitro transcription of anorexigenic/orexigenic neuropeptides in HEK293 cells via Foxo1-induced AgRP promoter activity (Sasaki et al., 2010) while SIRT1 upregulation in the brain induced in vivo anxiety via increased transcription of genes encoding monoamine oxidase-A (Mo-A) enzyme (Mo-A inhibitors are involved in clinical depression and anxiety treatment) (Libert et al., 2011). This evidence concerns the gene SIRT1 and major depressive disorder.