Formation and maturation of endocrine pancreas progenitors

 描述(由申请人提供)：由于移植的人类胰岛的可获得性和短期功能有限，人们对1型糖尿病患者胰岛素独立的厚望有所减弱。因此，通过干细胞的引导分化或其他成熟细胞的转分化来开发替代细胞已经成为治疗糖尿病的一个可行的前景。获得？细胞表型的低效率将注意力集中在控制胰腺向内分泌前体细胞发育转变的因素上。我们已经确定，在这一转变过程中表达的两种转录因子Pdx1和Oc1的协同作用，通过直接调节前内分泌基因Ngn3和参与交叉调节的转录网络，有助于小鼠内分泌祖细胞及其后代的形成和成熟。我们假设Pdx1-Oc1的相互作用在正常发育和接受性祖细胞中驱动内分泌胰腺基因程序的诱导。我们通过(1)描述Pdx1和Oc1在胚胎发育过程中的遗传相互作用，(2)确定Pdx1和Oc1是否建立了一个允许的表观遗传学图景来激活？细胞谱系的基因，以及(3)确定Pdx1和Oc1的功能组合是否可以促进活体、人胰管细胞和人胚胎干细胞中？细胞的形成和功能，来检验这一假说。这些研究使用了体外和体内的方法，使用了老鼠和人类的模型系统。成功完成所提出的目标将揭示生化、表观遗传和发育的作用机制，通过Pdx1和Oc1合作建立内分泌和？细胞谱系。这些信息可用于定向分化和转分化策略，以从干细胞、祖细胞或其他非？细胞产生新的功能齐全的？细胞。

 DESCRIPTION (provided by applicant): The high hopes of insulin-independence for patients with type 1 diabetes have been tempered by the limited availability and short-term function of transplanted human islets. The development of alternate sources of ß cells, through guided differentiation of stem cells or transdifferentiation of other mature cells, has therefore emerged as a viable prospect for diabetes cure. The low efficiency of achieving the ß cell phenotype has focused attention on factors that govern the pancreatic to endocrine progenitor developmental transition. We have determined that the concerted actions of Pdx1 and Oc1, two transcription factors expressed during this transition, contribute to formation and maturation of endocrine progenitors and their descendants in mice by directly regulating the proendocrine gene Ngn3 and by participating in a cross-regulatory transcriptional network. We hypothesize that Pdx1-Oc1 interaction drives induction of the endocrine pancreas gene program during normal development and in receptive progenitor cells. We test this hypothesis by (1) characterizing the genetic interaction between Pdx1 and Oc1 during embryonic development, (2) determining whether Pdx1 and Oc1 establish a permissive epigenetic landscape for activation of genes of the ß cell lineage, and (3) by determining whether combined Pdx1 and Oc1 gain of function can promote ß cell formation and function in vivo, in human pancreatic duct cells and in human embryonic stem cells. These studies make use of ex vivo and in vivo approaches using both mouse and human model systems. Successful completion of the proposed aims will reveal biochemical, epigenetic, and developmental mechanisms of action whereby Pdx1 and Oc1 cooperate to establish the endocrine and ß cell lineages. This information can be used in directed differentiation and transdifferentiation strategies to generate new fully functional ß cels from stem cells, progenitor cells, or other non-ß cells.