Scientists unveil genetic mechanism linked to obesity caused by high-calorie foods – Zoo House News
High-calorie foods — high in fat, oil, and sugar — can taste good, but often cause overeating, which leads to obesity and major health problems. But what stimulates the brain to cause overeating?
Recently, it became clear that a gene called CREB-Regulated Transcription Coactivator 1 (CRTC1) is linked to obesity in humans. When CRTC1 is deleted in mice, they become obese, suggesting that CRTC1 functioning suppresses obesity. However, since CRTC1 is expressed in all neurons in the brain, the specific neurons responsible for obesity suppression and the mechanism present in these neurons remained unknown.
To elucidate the mechanism by which CRTC1 suppresses obesity, a research group led by Associate Professor Shigenobu Matsumura of the Graduate School of Human Life and Ecology at Osaka Metropolitan University focused on neurons expressing the melanocortin-4 receptor (MC4R) express. They hypothesized that CRTC1 expression in MC4R-expressing neurons suppressed obesity, since mutations in the MC4R gene are known to cause obesity. Consequently, they created a mouse strain that normally expresses CRTC1 except in MC4R-expressing neurons, where it is blocked, to study the effect that the loss of CRTC1 in these neurons had on obesity and diabetes.
When fed a standard diet, mice lacking CRTC1 in MC4R-expressing neurons showed no changes in body weight compared to control mice. However, when the CRTC1-deficient mice were raised on a high-fat diet, they overfed, then became significantly more obese than the control mice and developed diabetes.
‘This study has unveiled the role played by the CRTC1 gene in the brain and part of the mechanism that discourages us from eating high-calorie, fatty and sugary foods,’ Professor Matsumura said. “We hope this leads to a better understanding of what drives people to overeat.”
Materials provided by Osaka Metropolitan University. Note: Content can be edited for style and length.