Abstract
Growing evidence demonstrates the important role of microRNAs (miRs) in regulating adipogenesis, obesity and insulin resistance. The miR-200b/a/429 cluster has been functionally characterized in mammalian reproduction; however, the potential role of the miR-200 family in adipocytes is poorly understood. The aim of our study was to investigate the physiological function of miR-200b/a/429 in the regulation of whole-body metabolism in terms of the activities and targets of this cluster in adipocytes. We generated adipocyte-specific miR-200b/a/429 knockout (ASKO) mice using a Cre-loxP system in which Cre expression was driven by the aP2 promoter. The ASKO and wild type (WT) littermate were fed a chow diet (CD) or high-fat-diet (HFD), and changes in body composition, metabolic parameters, energy homeostasis, glucose tolerance and insulin sensitivity were analyzed. The miR-200b/a/429 putative target genes were predicted and validated via luciferase reporter assays. We found that the HFD-fed ASKO mice gradually gained more body weight than the WT mice due to the increased adiposity. Decreased glucose tolerance and insulin sensitivity were also observed in the HFD-fed ASKO mice. Notably, the down-regulation of lipolysis-related genes and the decreased response to CL-316,243 stimulation in the HFD-fed ASKO mice suggested that these animals exhibited impaired lipolysis. In addition, the HFD-fed ASKO mice displayed impaired energy expenditure, indicating that the miR-200b/a/429 cluster is essential for developing adaptive responses to stressors such as HFD. For the first time, our studies demonstrated the essential role of miR-200b/a/429 in adipocytes in the regulation of HFD-induced whole-body metabolic changes.