The Role Of Long Non-coding RNA Gas5 In Mouse Pancreatic Beta Cell Function

Objective: Islet beta cells, specifically located in the pancreatic islets, are the body’s sole source of synthesis and secretion of insulin. Regulation of insulin secretion according to the demand of organisms, plays an important role in glucose homeostasis in the body. The function of islet beta cells is dysregulated or beta cells is damaged due to autoimmune destruction, which leads to the occurrence of T1 DM and T2 DM. The long non-coding RNA(long non-coding RNA, lnc RNA) is a transcription of the length of more than 200 nt RNA molecule, and don’t has protein-coding capacity itself. Lnc RNAs are strongly expressed in a tissue-specific and cell-type specific manner. The research has found that lnc RNAs involved in individual development, cell differentiation, cell cycle and other important life processes, and are closely related to major human diseases. Lnc RNAs regulate expression level of genes in the RNA form of epigenetic, transcriptional, post-transcriptional. Recent studies have found that the abnormal expression of lnc RNAs in diabetic patients islets, suggesting that lnc RNAs may be involved in the development of diabetes. But reports about lnc RNA in diabetes research are less. Growth arrest specific transcript 5(Gas5) is located in chromosome 1. In vivo, the gas5 gene is ubiquitously expressed in mouse tissues during development and adult life. And the Gas5 is regulated in mammalian cell growth, differentiation and development process through transcriptional andpost-transcriptional processes. But the role of Gas5 in regulation of adult islet overall function remains to be elucidated. This research aims at two levels of cell and primary islet level to investigate the role of Gas5 in mouse islet cell function, aiming at further enriching and improving gene regulatory network of islet function.Methods: The expression of Gas5 was detected in C57 mice multiple tissues and db/db male mice islet during diabetic hyperglycemia progression by real-time RT-PCR. Specific small interfering RNA(si RNA) was used to knockdown Gas5 in vitro and primary islet. MIN6 cells proliferation, apoptosis, insulin biosynthesis and secretion were analyzed by flow cytometry, radioimmunoassay(RIA), Western blotting techniques.Results: We found that Gas5 is highly expressed in mouse pancreas compared to other tissues, mainly located in the pancreatic islets. Gas5 expression levels decreased in db/db mice during the hyperglycemia of diabetes. Glucose concentration could regulate Gas5 expression. Further, knockdown of Gas5 in vitro resulted in beta cell cycle arrest, decreased insulin synthesis and secretion, but had no effect on beta cell apoptosis. At the same time, Ins2 m RNA level decreased, and Pdx-1, Maf A expression dropped significantly in m RNA and protein levels. Knockdown of Gas5 in Primary pancreatic islet cells showed Ins2 m RNA decreased, and Pdx-1and Maf A m RNA level shows consistent decrease.Conclusion: Our group confirmed that Gas5 can participate in the synthesis and secretion of insulin to maintain islet function in adult mice.In db/db mice, a T2 DM animal model, Gas5 expression levels decreased during the hyperglycemia. Down-regulation of Gas5 expression revealed that Gas5 may be involved in the pathogenesis of T2 DM, thus in the future lnc RNAs can be used as a new target for diabetes research.