The Effect of dietary fatty acids on the recruitment of brown‐like adipocytes in inguinal white adipose tissue

Abstract

The physiological significance of brown adipose tissue (BAT) in energy metabolism in adult humans has been recently re‐evaluated. The evidence from recent studies indicates a potential of converting white to brown adipocytes in white adipose tissue (WAT). Herein, we explored the regulatory effect of dietary fatty acids on this conversion in WAT. We found that BAT‐specific UCP1 was expressed at a significantly higher level in inguinal adipose tissue (ING) compared to epididymal adipose tissue in mice. High fat diet (HFD) modulated UCP1 expression in BAT and ING in a different manner. After one week of HFD, UCP1 was increased in BAT, but not in ING of mice. However, UCP1 was dramatically decreased after chronic HFD feeding in both tissues. Additionally, we examined the effects of saturated and polyunsaturated fatty acids on the differentiation of brown‐like adipocytes in primary culture of stromal‐vascular (SV) cells from ING of normal mice. Fatty acids were added to SV cell culture either during 8 days of differentiation or after differentiation for 24 hours. In differentiated adipocytes, 24h treatment with palmitate significantly reduced UCP1, while n‐3 fatty acid (EPA) treatment did not change UCP1 expression. However, UCP1 and PGC1α expression was significantly increased in SV cell cultures after 8‐ day EPA treatment. Our data suggests that EPA is capable of inducing the differentiation of inguinal SV cells into brown‐like adipocytes, but failed to induce UCP1 expression in mature white adipocytes. We conclude that HFD or saturated FA reduces UCP1, while EPA has a potential to increase the recruitment of brown‐like adipocytes in inguinal WAT.Grant Funding Source : General Mills Foundation, MN Obesity Consortium