RNA-sequencing analysis reveals the potential contribution of lncRNAs in palmitic acid-induced insulin resistance of skeletal muscle cells

Abstract

Insulin resistance (IR) has been considered as the common pathological basis and developmental driving force for most metabolic diseases. Long noncoding RNAs (lncRNAs) have emerged as pivotal regulators in modulation of glucose and lipid metabolism. However, the comprehensive profile of lncRNAs in skeletal muscle cells under the insulin resistant status and the possible biological effects of them were not fully studied. In this research, using C2C12 myotubes as cell models in vitro, deep RNA-sequencing was performed to profile lncRNAs and mRNAs between palmitic acid-induced IR C2C12 myotubes and control ones. The results revealed that a total of 144 lncRNAs including 70 up-regulated and 74 down-regulated (|fold change| > 2, q < 0.05) were significantly differentially expressed in palmitic acid-induced insulin resistant cells. In addition, functional annotation analysis based on the Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases revealed that the target genes of the differentially expressed lncRNAs were significantly enriched in fatty acid oxidation, lipid oxidation, PPAR signaling pathway, and insulin signaling pathway. Moreover, Via qPCR, most of selected lncRNAs in myotubes and db/db mice skeletal muscle showed the consistent expression trends with RNA-sequencing. Co-expression analysis also explicated the key lncRNA-mRNA interactions and pointed out a potential regulatory network of candidate lncRNA ENSMUST00000160839. In conclusion, the present study extended the skeletal muscle lncRNA database and provided novel potential regulators for future genetic and molecular studies on insulin resistance, which is helpful for prevention and treatment of the related metabolic diseases. sensitivity and whole-body metabolism. For example, perturbed heterogeneous nuclear ribonucleoprotein A1-induced turbulences in glucose homeostasis in the skeletal muscle could accelerate systemic IR under both basal and high-fat induced conditions [7]. Conversely, activating mTOR signaling, improved insulin sensitivity in the skeletal muscle, which could enhance whole-body metabolism via weight loss and an increased fatty acid oxidation capacity in the adipose tissue and liver [8,9]. Studies have shown that among the widely recognized mechanisms underlying IR in the skeletal muscle, quite a few studies displayed that accumulation of 'toxic' lipid metabolites was considered as an important contributor to IR in skeletal muscle [10][11][12][13][14]. Lipid-induced IR has been associated with different cellular events in skeletal muscle cells, including impaired insulin signaling transduction of IRS1-PI3K [15], activation of inflammatory and pro-inflammatory cytokines [16], abnormally accumulation of ceramides [17], and mitochondrial dysfunction [18]. Therefore, the factors or the mechanisms underlying IR in the skeletal muscle, which are induced by lipid overload, must be explored.Long noncoding RNAs (lncRNAs), transcribed by RNA polymerase II, is a kind of RNA molecules with lengths of more than 200 nucleot...

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