Dietary Curcumin Intervention Targets Mouse White Adipose Tissue Inflammation and Brown Adipose Tissue UCP1 Expression.

OBJECTIVE: This study aimed to determine whether dietary curcumin intervention targets both white adipose tissue (WAT) inflammation and brown adipose tissue (BAT)-mediated energy expenditure.

METHODS: C57BL/6J mice were fed with a low-fat diet, high-fat diet (HFD), or HFD plus curcumin. In addition to assessing the effect of curcumin intervention on metabolic profiles, this study assessed WAT macrophage infiltration and composition and inflammatory cytokine production. Metabolic cages were applied for determining energy expenditure. Raw264.7 (ATCC, Manassas, Virginia) and other cell models were utilized to test the in vitro effect of curcumin treatment.

RESULTS: Curcumin intervention reduced WAT macrophage infiltration and altered macrophage functional polarity, as the ratio of M2-like versus M1-like macrophages increased after curcumin intervention. Curcumin treatment reduced M1-like macrophage markers or proinflammation cytokine expression in both macrophages and adipocytes. Curcumin intervention also increased energy expenditure and body temperature in response to a cold challenge. Finally, the in vivo and in vitro investigations suggested that curcumin increased expression of uncoupling protein 1 (UCP1), possibly involving PPAR-dependent and -independent mechanisms.

CONCLUSIONS: Curcumin intervention targets both WAT inflammation and BAT UCP1 expression. These observations advanced our knowledge on the metabolic beneficial effects of the curry compound curcumin, bringing us a novel perspective on dietary polyphenol research.