title: Inhibition of uncoupling protein 2 by genipin reduces insulin-stimulated glucose uptake in 3T3-L1 adipocytes.
abstract: Uncoupling protein 2 (UCP2) was reported to be involved in insulin-glucose homeostasis, based on well established event that inhibition of UCP2 stimulates insulin secretion in pancreatic beta-cells. However, the role of UCP2 on insulin-stimulated glucose uptake in adipose tissue, which is an indispensable process in insulin-glucose homeostasis, remains unknown. In this study, UCP2 was inhibited by genipin in 3T3-L1 adipocytes, which increased mitochondrial membrane potential, intracellular ATP level and production of reactive oxygen species (ROS). Importantly, insulin-stimulated glucose uptake in 3T3-L1 adipocytes was largely impaired in the presence of genipin, and recovered by CCCP, a mitochondrial uncoupler. Furthermore, genipin leaded to suppression of insulin signal transduction through hyperactivation of c-Jun N-terminal kinase (JNK) and subsequent serine phosphorylation of insulin receptor substrate-1 (IRS-1). These results suggest that mitochondrial uncoupling in adipocytes positively regulates insulin-stimulated glucose uptake in adipocytes, and UCP2 may play an important role in insulin resistance.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Xujia
authors.initials: X
authors.lastname: Zhang
mesh_terms: D041721:3T3-L1 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology; D007333:Insulin Resistance; D007473:Ion Channels / Q000037:antagonists & inhibitors*; D057889:Iridoid Glycosides; D039823:Iridoids / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors*; D008954:Models, Biological; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000071246:Uncoupling Protein 2
chemical_list: D000873:Anthracenes; D007328:Insulin; D007473:Ion Channels; D057889:Iridoid Glycosides; D039823:Iridoids; D024101:Mitochondrial Proteins; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; C000604390:Ucp2 protein, mouse; D000071246:Uncoupling Protein 2; C432165:pyrazolanthrone; D000255:Adenosine Triphosphate; C007834:genipin; D048031:JNK Mitogen-Activated Protein Kinases; D005947:Glucose