Background/Aims: The islet is an important endocrine organ to secrete insulin to regulate the metabolism of glucose and maintain the stability of blood glucose. Long noncoding RNAs (lncRNAs) are involved in a variety of biological functions and play key roles in many diseases, including type 2 diabetes (T2D). The aim of this study was to determine whether lncRNA-p3134 is associated with glucose metabolism and insulin signaling in pancreatic β cells. Methods: LncRNA microarray technology was used to identify the differentially expressed circulating lncRNAs in T2D patients. RT-PCR analyses were performed to determine the expression of lncRNA-p3134 in 30 pairs of diabetic and non-diabetic patients. The correlation of lncRNA-p3134 to clinical data from T2D patients was analyzed. LncRNA-p3134 was overexpressed in Min6 cells and db/db mice by adenovirus-mediated technology. CCK-8, TUNEL, Western blot, glucose-stimulated insulin secretion (GSIS), ELISAs and immunochemistry were performed to determine the effect of lncRNA-p3134 on proliferation, apoptosis and insulin secretion both in vitro and vivo. Results: The circulating level of lncRNA-p3134 was higher in diabetic patients than in non-diabetic controls and was correlated with fasting blood glucose and HOMA-β levels. The lncRNA-p3134 had risen by 4 times in serum exosomes but nearly unchanged in exosome-free samples. The secretion of lncRNA-p3134 was dynamically modulated by glucose in both Min6 cells and isolated mouse islet cells. LncRNA-p3134 positively regulate GSIS through promoting of key regulators (Pdx-1, MafA, GLUT2 and Tcf7l2) in β cells. In addition, the overexpression of lncRNA-p3134 resulted in a decreased apoptosis ratio and partially reversed the glucotoxicity effects on GSIS function in Min6 cells. The restoration of insulin synthesis and secretion the increase of the insulin positive cells areas by upregulation of lncRNA-p3134 in db/db mice confirmed the compensatory role of lncRNA-p3134 to preserve β-cell function. Furthermore, a protective effect of lncRNA-p3134 on GSIS by positive modulation of PI3K/Akt/mTOR signaling was also confirmed. After blocking the PI3K/AKT signals with their specific inhibitor, the effect of overexpressed lncRNA-p3134 on insulin secretion was obviously attenuated. Conclusion: Taken together, the results of this study provide new insights into lncRNA-p3134 regulation in pancreatic β cells and provide a better understanding of novel mechanism of glucose homeostasis.
MicroRNAs (miRNAs) play important roles as significant biomarkers in disease diagnostics. Here, an electrochemical biosensor was developed for the quick, sensitive, and specific detection of miRNAs from humanserum samples using three-dimensional (3D) DNA tetrahedron-structured probes (TSPs) and duplex-specific nuclease (DSN). The designed TSPs were composed of a recognition sequence that corresponded to a target miRNA and a Gquadruplex sequence that was combined with hemin to mimic the biocatalytic functions for H 2 O 2 reduction and L-cysteine oxidation. After hybridization with miRNA, the TSPs were immobilized on the Au electrode to shape the DNA−RNA double strands, which could be discriminated by DSN for hydrolysis of the DNA in the heteroduplexes to generate significant change in the reduction currents. Under optimal conditions, the biosensor showed a wide linear response ranging from 0.1 fM to 0.1 pM, with a low detection limit of 0.04 fM. Meanwhile, the method showed acceptable accuracy and precision for the determination of miRNAs in serum after a series of assessments.
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