A major role of insulin in promoting obesity-associated adipose tissue inflammation
| Autor: | Anouch Matevossian, Laura V. Danai, Jason K. Kim, Adilson L. Guilherme, Dae Young Jung, Jessica Cohen, Hye Lim Noh, Lauren Heyda, Sarah M. Nicoloro, David J. Pedersen, Juerg R. Straubhaar, Michael P. Czech |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
lcsh:Internal medicine
medicine.medical_specialty medicine.medical_treatment Adipose tissue 030209 endocrinology & metabolism Inflammation Hyperinsulinemia 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Insulin resistance Downregulation and upregulation Internal medicine Adipocyte medicine Obesity lcsh:RC31-1245 Molecular Biology 030304 developmental biology 2. Zero hunger 0303 health sciences business.industry Insulin Cell Biology medicine.disease Endocrinology chemistry Lipogenesis Original Article medicine.symptom business |
| Zdroj: | Molecular Metabolism Molecular Metabolism, Vol 4, Iss 7, Pp 507-518 (2015) |
| ISSN: | 2212-8778 |
| DOI: | 10.1016/j.molmet.2015.04.003 |
| Popis: | Objective Adipose tissue (AT) inflammation is associated with systemic insulin resistance and hyperinsulinemia in obese rodents and humans. A longstanding concept is that hyperinsulinemia may promote systemic insulin resistance through downregulation of its receptor on target tissues. Here we tested the novel hypothesis that insulin also impairs systemic insulin sensitivity by specifically enhancing adipose inflammation. Methods Circulating insulin levels were reduced by about 50% in diet-induced and genetically obese mice by treatments with diazoxide or streptozotocin, respectively. We then examined AT crown-like structures, macrophage markers and pro-inflammatory cytokine expression in AT. AT lipogenesis and systemic insulin sensitivity was also monitored. Conversely, insulin was infused into lean mice to determine its affects on the above parameters. Results Lowering circulating insulin levels in obese mice by streptozotocin treatment decreased macrophage content in AT, enhancing insulin stimulated Akt phosphorylation and de novo lipogenesis (DNL). Moreover, responsiveness of blood glucose levels to injected insulin was improved by streptozotocin and diazoxide treatments of obese mice without changes in body weight. Remarkably, even in lean mice, infusion of insulin under constant euglycemic conditions stimulated expression of cytokines in AT. Consistent with these findings, insulin treatment of 3T3-L1 adipocytes caused a 10-fold increase in CCL2 mRNA levels within 6 h, which was blocked by the ERK inhibitor PD98059. Conclusion Taken together, these results indicate that obesity-associated hyperinsulinemia unexpectedly drives AT inflammation in obese mice, which in turn contributes to factors that suppress insulin-stimulated adipocyte DNL and systemic insulin sensitivity. Highlights • Adipose tissue inflammation correlates with hyperinsulinemia in obese mice and humans independent of BMI. • Reduction of hyperinsulinemia ameliorates adipose tissue inflammation and enhances systemic insulin sensitivity. • Insulin increases adipose inflammation in vivo and enhances adipocyte MCP-1 expression in vitro through ERK activation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|