title: Overexpression of micro ribonucleic acid 29, highly up-regulated in diabetic rats, leads to insulin resistance in 3T3-L1 adipocytes.
abstract: Micro-RNAs (miRNAs) have been suggested to play pivotal roles in multifarious diseases associated with the posttranscriptional regulation of protein-coding genes. In this study, we aimed to investigate the function of miRNAs in type 2 diabetes mellitus. The miRNAs expression profiles were examined by miRNA microarray analysis of skeletal muscles from healthy and Goto-Kakizaki rats. We identified four up-regulated miRNAs, and 11 miRNAs that were down-regulated relative to normal individuals. Among induced miRNAs were three paralogs of miR-29, miR-29a, miR-29b, and miR-29c. Northern blotting further confirmed their elevated expression in three important target tissues of insulin action: muscle, fat, and liver of diabetic rats. Adenovirus-mediated overexpression of miR-29a/b/c in 3T3-L1 adipocytes could largely repress insulin-stimulated glucose uptake, presumably through inhibiting Akt activation. The increase in miR-29 level caused insulin resistance, similar to that of incubation with high glucose and insulin in combination, which, in turn, induced miR-29a and miR-29b expression. In this paper, we demonstrate that Akt is not the direct target gene of miR-29 and that the negative effects of miR-29 on insulin signaling might be mediated by other unknown intermediates. Taken together, these data reveal the crucial role of miR-29 in type 2 diabetes.
authors.affiliation: The National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, The Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China.
authors.forename: Aibin
authors.initials: A
authors.lastname: He
authors.forename: Liuluan
authors.initials: L
authors.lastname: Zhu
authors.forename: Nishith
authors.initials: N
authors.lastname: Gupta
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Chang
authors.forename: Fude
authors.initials: F
authors.lastname: Fang
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D003920:Diabetes Mellitus / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008297:Male; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007328:Insulin; C526366:MIRN29 microRNA, rat; D035683:MicroRNAs; D051057:Proto-Oncogene Proteins c-akt