The Role of Dietary Phytoestrogens and the Nuclear Receptor PPARγ in Adipogenesis: An in Vitro Study.

Abstract

Background:Phytoestrogens, naturally occurring plant chemicals, have long been thought to confer beneficial effects on human cardiovascular and metabolic health. However, recent epidemiological studies, have yielded conflicting outcomes, in which phytoestrogen consumption was both positively and negatively correlated with adiposity. Interestingly, several dietary phytoestrogens are known to stimulate or inhibit the activity of the peroxisome proliferator-activated receptor gamma (), a key physiological regulator of adipogenesis.Objective:The objective of this study was to test the hypothesis that the pro- or anti-adipogenic activity of phytoestrogen chemicals is related to the ability to activate in adipocytes.Methods:The effects of resveratrol and the soy isoflavones genistein and daidzein on adipogenesis were examined in cell-based assays using the 3T3-L1 cell model. In parallel, ligand-mediated alterations in target gene expression were measured by quantitative polymerase chain reaction. The agonist/antagonist activities of phytoestrogens on were further assessed by quantifying their ability to affect recruitment of transcriptional cofactors to the receptor.Results:Resveratrol displayed significant anti-adipogenic activities as exhibited by the ability to antagonize -dependent adipocyte differentiation, down-regulate genes involved in lipid metabolism, block cofactor recruitment to , and antagonize the effects of the agonist rosiglitazone. In contrast, genistein and daidzein functioned as agonists while also displaying pro-adipogenic activities.Conclusions:These data provide biological evidence that the pro- or anti-obesity effects of phytoestrogens are related to their relative agonist/antagonist activity on . Thus, -activation assays may enable the screening of dietary components and identification of agents with adipogenic activities. https://doi.org/10.1289/EHP3444