长链非编码RNA在胚胎干细胞向定型内胚层细胞分化中的作用与分子机制研究

Embryonic stem cells (ESCs) are totipotent stem cells that have broad differentiation capabilities. Upon induction, ESCs can differentiate into a variety of defined lineages including definitive endoderm. Cells from definitive endoderm give rise to the epithelial lining of respiratory and digestive tracts as well as several important organs including pancreas and liver. Thus, directed differentiation of ESCs to definitive endoderm receives much interest for its strong potential in regenerative medicine. Currently, the differentiation process suffers from low efficiency and lack of robust signature gene expression in more terminally differentiated cells such as hepatocytes. Therefore, understanding the molecular mechanism of the differentiation process could provide useful insights and lead to development of an improved method. LncRNAs are a group of large non-coding RNAs usually with >200nt in length. By binding with other cellular factors, lncRNAs can regulate expression of multiple downstream genes through transcriptional regulation. lncRNAs have been found to regulate many cellular activities but their involvement in definitive endoderm differentiation is still elusive. Here we hypothesize that lncRNAs can serve as a molecular switch that regulates differentiation of ESCs into definitive endoderm. By analyzing lncRNA expression changes during the differentiation and executing functional studies using a variety of cellular and biochemical approaches, this application aims to dissect the molecular mechanisms of lncRNA-mediated regulation of definitive endoderm differentiation. This study will not only offer new mechanistic insights on gene regulatory network of definitive endoderm differentiation but also help to develop an improved method that could have better therapeutic potential for regenerative medicine.

胚胎干细胞（ESCs）是全能型干细胞，能定向分化为多种组织包括定型内胚层。后者可形成呼吸和消化道上皮及相关器官和腺体如胰腺和肝脏。其潜在的应用价值使得定型内胚层细胞定向分化一直是再生医学研究的热点问题。目前，该过程仍受低效率和所得体细胞不够成熟的困扰。因此，进一步了解该过程的分子调节机制显得尤为重要。LncRNAs是长度通常超过200个核苷酸的长链非编码RNA。其通过和胞内蛋白结合，可调控多个下游基因的转录表达。LncRNA参与调解多种细胞活动，但其是否参与调控ESCs向定型内胚层的定向分化过程并不清楚。我们的设想是：lncRNAs可作为分子开关，调控ESCs向定型内胚层的分化。通过分析lncRNAs的表达谱变化，并利用多种细胞和生化手段，我们拟阐明lncRNAs对定型内胚层分化过程的具体调控机制。此研究不仅能为该过程提供新的分子调节机制，也能为进一步开发更高效的分化方法提供良好的理论支持