消化器官原基的前体细胞谱系与命运决定机制

The digestive organs, including liver, pancreas, and gut, originate from the endoderm. They are responsible for the digestive and endocrinal functions in vertebrate. The stage from progenitor cells in the early endoderm to organ primordia is the early developmental stage of digestive organs, which is also an important stage of stem cell differentiation or mature cell transdifferentiation in the regenerative medicine strategies. In order to accurately map the progenitor region of individual digestive organ in the early endoderm, and to characterize lineage and fate determination of progenitors, we have established single cell labeling and lineage tracing techniques in zebrafish. This project will focus on the progenitor cell lineage and fate determination of digestive organ primordia based on the following five aims. 1) Establishment of single cell-resolution lineage map of digestive organ progenitors. 2) Characterization of cell differentiation potential and behaviors from early endoderm to organ primordium formation. 3) Mechanisms of lineage and fate determination of digestive organ progenitors. 4) Balance of liver and pancreas progenitor regions regulated by sfrp1bb. 5) Repression of hepatic differentiation in the gut progenitors by shox2.

消化器官起源于内胚层，包括肝脏、胰腺和消化道，发挥消化和内分泌等生理功能。从早期内胚层中的前体细胞到器官原基细胞是消化器官发育的基础阶段，也是再生医学策略中干细胞分化或其它细胞转分化为消化器官功能细胞的重要阶段。为明确各消化器官前体细胞在早期内胚层中的准确定位区域，揭示其发育为器官原基的谱系发生和命运决定过程和调控机制，同时作为去年已结题重点项目的延续和拓展，本项目通过建立早期内胚层单细胞标记与谱系示踪技术，致力于从以下五个部分研究消化器官原基的前体细胞谱系和命运决定机制：1）早期内胚层对应各消化器官原基的单细胞分辨率谱系图谱的建立；2）从早期内胚层到消化器官原基形成过程的细胞分化潜能和细胞行为研究；3）早期内胚层中各消化器官前体细胞谱系发生和命运决定机制研究；4）sfrp1bb调控肝脏和胰腺前体细胞平衡及原基发生的分子机制研究；5）shox2在消化道原基细胞中抑制肝向分化的分子机制研究。

本项目顺利完成任务书中各项研究计划，主要进展和成果包括：1）通过发展斑马鱼胚胎原始内胚层单细胞精准标记和短时程示踪技术，完成了第一张可视化的原始内胚层单细胞分辨率谱系图谱，并利用该图谱发现细胞周期对胰腺命运决定的调控机制。2）揭示消化器官发育过程中前肠和胰腺前体细胞对抗肝向诱导信号的分子机制，发现肠道前体细胞通过Cdx1b-Sfrp5分子级联对抗肝向诱导信号以避免被错误诱导为肝细胞。3）揭示肝脏重度损伤后胆管细胞命运重塑和转分化为新生肝细胞的调控机制。4）鉴定了肝细胞响应饥饿的重要因子FTCD。5）发展了在斑马鱼幼鱼全鱼中多个基因表达的高灵敏高分辨同时检测方法。本项目实施五年来共发表论文18篇，代表性论文发表于PNAS（2篇）、Developmental Cell（2篇）、Hepatology（2篇）、Cell Reports（2篇）等知名期刊，并以项目负责人为第一完成人获得重庆市自然科学奖一等奖，圆满并超额完成研究目标。