title: miR-135a targets IRS2 and regulates insulin signaling and glucose uptake in the diabetic gastrocnemius skeletal muscle.
abstract: Although aberrant miRNA signatures are associated with diabetes, yet, the status and role of altered miRNAs in the diabetic skeletal muscle is currently poorly understood. Here, we report that 41 miRNAs are altered in the diabetic gastrocnemius skeletal muscle and of these, miR-135a that is identified as a critical regulator of myogenesis, is significantly up-regulated. IRS2 is predicted as its potential putative target and its levels are down-regulated in the diabetic gastrocnemius skeletal muscle. In C2C12 cells, while miR-135a levels decreased during differentiation, IRS2 levels were up-regulated. miR-135a significantly reduced IRS2 protein levels and its 3'UTR luciferase reporter activity and these were blunted by the miR-135a inhibitor and mutation in the miR-135a binding site. Knock-down of endogenous miR-135a levels increased IRS2 at the mRNA and protein levels. miR-135a also attenuated insulin stimulated phosphorylation and activation of PI3Kp85α and Akt and glucose uptake. miR-135a levels were also found to be elevated in the human diabetic skeletal muscle. In-vivo silencing of miR-135a alleviated hyperglycemia, improved glucose tolerance and significantly restored the levels of IRS2 and p-Akt in the gastrocnemius skeletal muscle of db/db mice without any effect on their hepatic levels. These suggest that miR-135a targets IRS2 levels by binding to its 3'UTR and this interaction regulates skeletal muscle insulin signaling.
authors.affiliation: CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi-110 007, India.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Agarwal
authors.forename: Rohit
authors.initials: R
authors.lastname: Srivastava
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Srivastava
authors.forename: Shakir
authors.initials: S
authors.lastname: Ali
authors.forename: Malabika
authors.initials: M
authors.lastname: Datta
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D005947:Glucose / Q000235:genetics / Q000378:metabolism / Q000493:pharmacokinetics*; D005951:Glucose Tolerance Test; D057809:HEK293 Cells; D006801:Humans; D006943:Hyperglycemia / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000235:genetics / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D024510:Muscle Development / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D020413:3' Untranslated Regions; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526298:Irs2 protein, mouse; D035683:MicroRNAs; C549289:Mirn135 microRNA, mouse; D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose