Irisin regulates thermogenesis and lipolysis in 3T3-L1 adipocytes.

BACKGROUND:Adipose tissue plays a pivotal role in the development and progression of the metabolic syndrome which along with its complications is an epidemic of the 21st century. Irisin is an adipo-myokine secreted mainly by skeletal muscle and targeting, among others, adipose tissue. In brown adipose tissue it upregulates uncoupling protein-1 (UCP1) which is responsible for mitochondrial non-shivering thermogenesis. METHODS:Here we analyzed the effects of irisin on the metabolic activity of 3T3-L1 derived adipocytes through a mitochondrial flux assay. We also assessed the effects of irisin on the intracellular signaling through Western Blot. Finally, the gene expression of ucp1 and lipolytic genes was examined through RT-qPCR. RESULTS:Irisin affects mitochondrial respiration and lipolysis in a time-dependent manner through the regulation of PI3K-AKT pathway. Irisin also induces the expression of UCP1 and the regulation of NF-κB, and CREB and ERK pathways. CONCLUSION:Our data supports the role of irisin in the induction of non-shivering thermogenesis, the regulation of energy expenditure and lipolysis in adipocytes. GENERAL SIGNIFICANCE:Irisin may be an attractive therapeutic target in the treatment of obesity and related metabolic disorders.