Journal Article

MAP3K8 (TPL2/COT) Affects Obesity-Induced Adipose Tissue Inflammation without Systemic Effects in Humans and in Mice

van Diepen, Janna A., Sparrer, Helmut, Tack, Cees J., Joosten, Leo A. B., van Essen, Peter, Jansen, Henry, Hijmans, Anneke, Matsuguchi, Tetsuya, Stienstra, Rinke, Ballak, Dov B., Netea, Mihai G.

2014

Overview

Chronic low-grade inflammation in adipose tissue often accompanies obesity, leading to insulin resistance and increasing the risk for metabolic diseases. MAP3K8 (TPL2/COT) is an important signal transductor and activator of pro-inflammatory pathways that has been linked to obesity-induced adipose tissue inflammation. We used human adipose tissue biopsies to study the relationship of MAP3K8 expression with markers of obesity and expression of pro-inflammatory cytokines (IL-1β, IL-6 and IL-8). Moreover, we evaluated obesity-induced adipose tissue inflammation and insulin resistance in mice lacking MAP3K8 and WT mice on a high-fat diet (HFD) for 16 weeks. Individuals with a BMI >30 displayed a higher mRNA expression of MAP3K8 in adipose tissue compared to individuals with a normal BMI. Additionally, high mRNA expression levels of IL-1β, IL-6 and IL-8, but not TNF -α, in human adipose tissue were associated with higher expression of MAP3K8. Moreover, high plasma SAA and CRP did not associate with increased MAP3K8 expression in adipose tissue. Similarly, no association was found for MAP3K8 expression with plasma insulin or glucose levels. Mice lacking MAP3K8 had similar bodyweight gain as WT mice, yet displayed lower mRNA expression levels of IL-1β, IL-6 and CXCL1 in adipose tissue in response to the HFD as compared to WT animals. However, MAP3K8 deficient mice were not protected against HFD-induced adipose tissue macrophage infiltration or the development of insulin resistance. Together, the data in both human and mouse show that MAP3K8 is involved in local adipose tissue inflammation, specifically for IL-1β and its responsive cytokines IL-6 and IL-8, but does not seem to have systemic effects on insulin resistance.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adipose tissue / Adipose Tissue - immunology / Adipose Tissue - metabolism / Adipose Tissue - pathology / Animals / Arthritis / Authorship / Biology / Blood Proteins - analysis / Blotting, Western / Body fat / Body mass / Body Mass Index / Cancer / Cells, Cultured / Cytokines / Diabetes / Diet, High-Fat / Disease / Gene expression / Glucose / Glucose Tolerance Test / Health risks / High fat diet / Humans / Immunoenzyme Techniques / Infections / Infiltration / Inflammation / Inflammation - etiology / Inflammation - metabolism / Inflammation - pathology / Insulin / Insulin - metabolism / Insulin Resistance / Interleukin 6 / Interleukin 8 / Interleukin-1beta - genetics / Interleukin-1beta - metabolism / Interleukin-6 - genetics / Interleukin-6 - metabolism / Interleukin-8 - genetics / Interleukin-8 - metabolism / kinase / Kinases / Macrophages / MAP Kinase Kinase Kinases - genetics / MAP Kinase Kinase Kinases - metabolism / MAP Kinase Kinase Kinases - physiology / Medicine / Metabolic disorders / Mice / Mice, Inbred C57BL / Mice, Knockout / Nutrition research / Obesity / Obesity - complications / Obesity - metabolism / Obesity - pathology / oncoprotein / Proteins / Proto-Oncogene Proteins - genetics / Proto-Oncogene Proteins - metabolism / Proto-Oncogene Proteins - physiology / Quality / Real-Time Polymerase Chain Reaction / Reverse Transcriptase Polymerase Chain Reaction / RNA / RNA, Messenger - genetics / Rodents / Signal transduction / tpl-2 / Tumor necrosis factor / Tumor Necrosis Factor-alpha - genetics / Tumor Necrosis Factor-alpha - metabolism / Tumor necrosis factor-TNF / Type 2 diabetes