抄録
Overnutrition and physical inactivity lead to obesity, which is associated with adipocyte hypertrophy and hyperplasia. The body stores lipid primarily in white adipocytes, but beige adipocytes are also present in white adipose tissue. Beige adipocytes are heat-producing cells that convert energy obtained from lipid consumption into heat through mitochondrial uncoupled protein 1 (UCP-1), and this heat-producing capacity is considered to be anti-obesity. However, heat production is inhibited by the chronic inflammation induced in obese adipose tissue by macrophage infiltration. Chronic inflammation also suppresses the expression of UCP-1 and reduces thermogenesis. Therefore, food compounds with anti-inflammatory properties are expected to exert anti-obesity effects by restoring UCP-1 expression and increasing fat consumption in beige adipocytes.
Food-derived compounds have been reported to increase UCP-1 expression when administered directly to animals. When an obesity model is used to evaluate the function of food-derived compounds, some of the increased expression of UCP-1 could be attributed to its anti-inflammatory effects. It is also possible that food-derived compounds that were not found to increase UCP-1 expression could restore UCP-1 expression in the obese state due to their anti-inflammatory effects. To elucidate the mechanism of how food-derived compounds increase UCP-1 expression at the cellular level, it is necessary to perform independent experiments on adipocytes and macrophages. Therefore, we established an evaluation system to study the effects of food compounds with anti-inflammatory effects on beige adipocytes under reproduced inflammatory conditions induced by macrophages. Using this system, we analyzed 6-shogaol, which has already been reported to increase UCP-1 expression and have anti-inflammatory effects. The results showed that the expression of UCP-1 was restored by the anti-inflammatory effect of 6-shogaol. The newly developed evaluation system using macrophage culture supernatant is a useful system for evaluating food-derived compounds with anti-inflammatory effects.
