The E3 Ubiquitin Ligase Pellino3 Protects against Obesity-Induced Inflammation and Insulin Resistance

Diet-induced obesity can induce low-level inflammation and insulin resistance. Interleukin-1 beta (IL-1 beta) is one of the key proinflammatory cytokines that contributes to the generation of insulin resistance and diabetes, but the mechanisms that regulate obesity-driven inflammation are ill defined. Here we found reduced expression of the E3 ubiquitin ligase Pellino3 in human abdominal adipose tissue from obese subjects and in adipose tissue of mice fed a high-fat diet and showing signs of insulin resistance. Pellino3-deficient mice demonstrated exacerbated high-fat-diet-induced inflammation, IL-1 beta expression, and insulin resistance. Mechanistically, Pellino3 negatively regulated TNF receptor associated 6 (TRAF6)-mediated ubiquitination and stabilization of hypoxia-inducible factor 1 alpha (HIF1 alpha), resulting in reduced HIF1 alpha-induced expression of IL-1 beta. Our studies identify a regulatory mechanism controlling diet-induced insulin resistance by highlighting a critical role for Pellino3 in regulating IL-1 beta expression with implications for diseases like type 2 diabetes.