Project description:Obesity-induced inflammation metabolic dysfunction, but the mechanisms remain elusive. Here we showed that the innate immune factor IRF3 is a direct transcriptional regulator of glucose homeostasis through induction of endogenous FAHFA hydrolase Aig1 in adipocytes. Adipocyte-specific knockout IRF3 protects mice against high-fat diet-induced insulin resistance, whereas overexpression of IRF3 in adipocytes promotes insulin resistance on a high-fat diet. Furthermore, pharmacological inhibition of AIG1 reversed obesity-induced insulin resistance and restored glucose homeostasis in the setting of adipocyte IRF3 overexpression. We therefore, identify the adipocyte IRF3/AIG1 axis as a crucial link between obesity-induced inflammation and insulin resistance and suggest an approach for limiting the metabolic dysfunction accompanying obesity.
Project description:Estrogens are important for metabolic health. Individuals with low levels of circulating estrogens, including men and postmenopausal women, exhibit an elevated risk for developing obesity-associated metabolic syndromes. Chronic low-grade inflammation in the visceral adipose tissue (VAT) is a major contributor to metabolic dysfunction during obesity. Regulatory T cells (Tregs) in the VAT limit tissue inflammation and protect against obesity-associated metabolic disease. In this study, we identify opposing roles of estrogen receptor α (ERα) in regulating VAT Tregs in female mice under steady-state and obese conditions. At steady state, ERα restrained the age-dependent clonal expansion of specific VAT Treg subsets expressing the IL-33 receptor ST2. However, during obesity, ERα-deficiency predisposed females to the loss of ST2+ VAT Tregs, exacerbating VAT inflammation and insulin resistance. These findings indicate that ERα signaling protects against obesity-induced metabolic diseases by preserving metabolically protective ST2+ VAT Treg subsets, and the loss of this protection may contribute to the heightened metabolic risk in estrogen-deficient individuals.
Project description:Estrogens are important for metabolic health. Individuals with low levels of circulating estrogens, including men and postmenopausal women, exhibit an elevated risk for developing obesity-associated metabolic syndromes. Chronic low-grade inflammation in the visceral adipose tissue (VAT) is a major contributor to metabolic dysfunction during obesity. Regulatory T cells (Tregs) in the VAT limit tissue inflammation and protect against obesity-associated metabolic disease. In this study, we identify opposing roles of estrogen receptor α (ERα) in regulating VAT Tregs in female mice under steady-state and obese conditions. At steady state, ERα restrained the age-dependent clonal expansion of specific VAT Treg subsets expressing the IL-33 receptor ST2. However, during obesity, ERα-deficiency predisposed females to the loss of ST2+ VAT Tregs, exacerbating VAT inflammation and insulin resistance. These findings indicate that ERα signaling protects against obesity-induced metabolic diseases by preserving metabolically protective ST2+ VAT Treg subsets, and the loss of this protection may contribute to the heightened metabolic risk in estrogen-deficient individuals.
Project description:KDM4B (lysine demethylase 4B) in adipose tissues plays a critical role in energy balance, oxidation, lipolysis and thermogenesis. Loss of KDM4B in mice resulted in obesity associated with reduced energy expenditure and impaired adaptive thermogenesis. Mechanistically, we determined that KDM4B directly controls the expression of multiple metabolic genes.
