Nutritional State Affects the Expression of the Obesity-Associated Genes Etv5, Faim2, Fto, and Negr1

Obesity is a risk factor for type II diabetes, atherosclerosis, and some forms of cancer. Variation in common measures of obesity (e.g., BMI, waist/hip ratio) is largely explained by heritability. The advent of genome-wide association studies (GWAS) has made it possible to identify several genetic variants that associate with measures of obesity, but how exactly these genetic variants contribute to overweight has remained largely unresolved. One first hint is given by the fact that many of the associated variants reside in or near genes that act in the central nervous system, which implicates neuronal signaling in the etiology of obesity. Although the brain controls both energy intake and expenditure, it has more capacity to regulate energy intake rather than energy expenditure. In environments where food is abundant, this renders the body prone to weight increases. To gain more insight into the neurobiological mechanisms involved, we set out to investigate the effect of dietary exposure on the expression levels of obesity-associated genes in the ventro-medial hypothalamus (VMH)/arcuate nucleus (ARC) and the substantia nigra (SN)/ventral tegmental area (VTA), two brain regions that are implicated in feeding behavior. We show that the expression of Etv5, Faim2, Fto, Negr1 but not Sh2b1 is affected by nutritional state in these two areas, thereby providing insight into the relationship between nutritional state and expression levels of obesity-associated genes in two brain areas relevant to feeding.