title: CHANGES IN microRNA (miR) profile and effects of miR-320 in insulin-resistant 3T3-L1 adipocytes.
abstract: 1. MicroRNAs (miRNAs) play essential roles in many biological processes. It is known that aberrant miRNA expression contributes to some pathological conditions. However, it is not known whether miRNAs play any role in the development of insulin resistance in adipocytes, a key pathophysiological link between obesity and diabetes. 2. To investigate the function of miRNAs in the development of insulin resistance, using miRNA microarray analysis we compared miRNA expression profiles between normal insulinsensitive 3T3-L1 adipocytes and 3T3-L1 adipocytes rendered insulin resistant following treatment with high glucose (25mmol/L) and high insulin (1 mol/L). Furthermore, adipocytes were transfected with specific antisense oligonucleotides against miRNA-320 (anti-miR-320 oligo) and the effects on the development of insulin resistance were evaluated. 3. We identified 50 upregulated and 29 downregulated miRNAs in insulin-resistant (IR) adipocytes, including a 50-fold increase in miRNA-320 (miR-320) expression. Using bioinformatic techniques, the p85 subunit of phosphatidylinositol 3-kinase (PI3-K) was found to be a potential target of miR-320. In experiments with anti-miR-320 oligo, insulin sensitivity was increased in IR adipocytes, as evidenced by increases in p85 expression, phosphorylation of Akt and the protein expression of the glucose transporter GLUT-4, as well as insulin-stimulated glucose uptake. These beneficial effects of anti-miR-320 oligo were observed only in IR adipocytes and not in normal adipocytes. 4. In conclusion, the miRNA profile changes in IR adipocytes compared with normal 3T3-L1 adipocytes. Anti-miR-320 oligo was found to regulate insulin resistance in adipocytes by improving insulin–PI3-K signalling pathways. The findings provide information regarding a potentially new therapeutic strategy to control insulin resistance.
authors.affiliation: Department of Pharmacology, School of Pharmaceutical Science, Central South University, Changsha.
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Ling
authors.forename: He-Sheng
authors.initials: HS
authors.lastname: Ou
authors.forename: Shui-Dong
authors.initials: SD
authors.lastname: Feng
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Zhang
authors.forename: Qin-Hui
authors.initials: QH
authors.lastname: Tuo
authors.forename: Lin-Xi
authors.initials: LX
authors.lastname: Chen
authors.forename: Bing-Yang
authors.initials: BY
authors.lastname: Zhu
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Gao
authors.forename: Cao-Ke
authors.initials: CK
authors.lastname: Tang
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Yin
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Duan-Fang
authors.initials: DF
authors.lastname: Liao
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism*; D050156:Adipogenesis / Q000235:genetics; D000818:Animals; D058543:Class Ia Phosphatidylinositol 3-Kinase / Q000378:metabolism; D019295:Computational Biology; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000235:genetics*; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D013997:Time Factors; D014162:Transfection
chemical_list: D051275:Glucose Transporter Type 4; D007328:Insulin; D035683:MicroRNAs; C541056:Mirn320 microRNA, mouse; D016376:Oligonucleotides, Antisense; C495693:Slc2a4 protein, mouse; D058543:Class Ia Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose