The Role Of Long Non-coding RNA Meg3 In Mouse Pancreatic Beta Cell Function

Objective:The length of lncRNAs is more than 200 nt and don’t have protein-coding capacity. lncRNAs are expressed in a cell type and tissue specific manner. Several dozen lncRNAs are known to exert non-redundant roles in cell processes such as cell cycle, cell apoptosis and cell differentiation, however, dysregulation of lncRNAs leads to many human diseases. It was newly reported that islet-specific lncRNA has a relationship with diabetes. Mouse Meg3 is a maternally expressed imprinted gene, which is located in mouse distal 12 chromosome and homologous with human MEG3 genes. However, the role of Meg3 in regulation of adult islet overall function remains to be elucidated. The aim of this study was to explore the relationship between Meg3 and the function of beta cells.Methods:The expression of Meg3 was detected in Babl/c mice multiple tissues and NOD during diabetes progression by real-time RT-PCR. Meg3 expresson in MIN6 cells and primary islets (both in mice) induced by different glucose content was determined by real-time RT-PCR. Specific small interfering RNA (siRNA) was used to knockdown Meg3 in vitro and vivo. MIN6 cells apoptosis, proliferation and insulin biosynthesis were analyzed by MTT, flow cytometry, RIA and western blot techniques. Subsequently, ability of insulin synthesis and secretion was detected by IPGTT, ELISA, immunohistochemistry, western blot and real-time RT-PCR.Results:We found that Meg3 is abundantly expressed in mouse pancreas compared to other tissues. It was even further enriched in islet prepartions. Meg3 levels decreased in NOD mice during the pathogenesis of diabetes. Glucose content could regulate Meg3 expression. Further, knockdown of Meg3 in vitro increased beta cell apoptosis, decreased insulin synthesis and secretion, but had no effect on beta cell proliferation. At the same time, Ins2 mRNA level decreased and Pdxl, MafA expression dropped significantly in mRNA and protein levels. Moreover, Meg3 interference group(si-Meg3) in vivo showed slightly impaired glucose tolerance and decreased insulin secretion in IPGTT. Immunohistochemistry analysis also showed insulin positive cells areas decreased. Islet from si-Meg3 group showed reduced expression of MafA and Pdxl in mRNA and protein levels.Conclusion:This study suggests Meg3 play a role in beta cell insulin synthesis, secretion and apoptosis, thus offering a new targec for the diabetes development of preventive or therapeutic agent.