Formation of endocrine pancreas progenitors

描述（由申请人提供）：基于细胞的1型糖尿病治疗方法主要集中在单个或组合转录因子的表达上，这些转录因子可以驱动细胞特异性基因表达模式，并且大多数至少部分依赖于Pdx1（一种在胰腺早期发育和成熟细胞中具有关键调节作用的同源结构域转录因子）和Ngn3（一种关键的促内分泌转录因子，其瞬时表达特征为内分泌祖细胞）。然而，通过任何这些方法获得细胞表型的效率仍然很低，并且这些努力的保真度和稳定性尚未得到充分评估。虽然内胚层是可再生和有效地实现的，但随后的转换，如从胰腺祖细胞到内分泌胰腺祖细胞的转换，效率特别低。我们最近确定，Pdx1通过与Hnf6一起直接调节Ngn3，以及参与早期胰腺发育过程中的交叉调节转录因子网络，对小鼠内分泌祖细胞的规范有贡献。我们假设，了解转录因子Ngn3的表观遗传调控以及Pdx1和Hnf6在发育细胞的交叉调控转录因子网络中的作用，将有助于通过引导非细胞群体分化来提高细胞表型的效率、保真度和稳定性。因此，我们在AIM 1中提出：研究Ngn3在人类胰腺祖细胞中的遗传和表观遗传调控；AIM 2中提出：分析Pdx1和Hnf6在促进内分泌祖细胞规范中的遗传和分子相互作用；AIM 3中提出：通过全局占用和基因表达分析，确定Pdx1和Hnf6在内分泌胰腺祖细胞转录网络中的作用。首要的长期目标是利用从这些研究中获得的信息来优化胚胎干细胞和诱导性多能干细胞，以及可能的成熟谱系向细胞命运的引导转变。

DESCRIPTION (provided by applicant): Approaches to cell based therapies for type 1 diabetes have largely focused on the expression of a single or a combination of transcription factors that can drive ( cell specific patterns of gene expression, and most have relied at least in part on Pdx1, a homeodomain transcription factor with critical regulatory roles in early pancreas development and in the mature ( cell, and on Ngn3, a critical pro-endocrine transcription factor whose transient expression characterizes endocrine progenitors. However promising, the efficiency of achieving a ( cell phenotype by any of these approaches remains low, and the fidelity and stability of these efforts have not been fully evaluated. Although endoderm is achieved reproducibly and efficiently, subsequent transitions, such as from pancreatic progenitor to endocrine pancreatic progenitor, are achieved with particularly low efficiency. We recently determined that Pdx1 contributes to specification of endocrine progenitors in mice both by regulating Ngn3 directly in concert with Hnf6 and by participating in a cross-regulatory transcription factor network during early pancreas development. We hypothesize that understanding the epigenetic regulation of the transcription factor Ngn3 and the roles of Pdx1 and Hnf6 in the cross-regulatory transcription factor network of developing ( cells will inform efforts to improve the efficiency, fidelity and stability of the ( cell phenotype achieved through the guided differentiation of non-( cell populations. Therefore, we propose in AIM 1: To examine the genetic and epigenetic regulation of Ngn3 in human pancreas progenitors, in AIM 2: To analyze the genetic and molecular interactions between Pdx1 and Hnf6 in promoting endocrine progenitor specification, and in AIM 3: To define the role of Pdx1 and Hnf6 in the transcriptional network of endocrine pancreas progenitors through global occupancy and gene expression analysis. The overarching long-term goal is to utilize this information gained from these studies to optimize the guided transition of ES and iPS cells, and possibly mature lineages, toward a ( cell fate. PUBLIC HEALTH RELEVANCE: The high hopes for cell based therapy for type 1 diabetes have been tempered by the limited availability and short-term function of human islets for transplantation, leading to intense focus on alternate sources of (?cells. The overarching goal of the proposed studies is to optimize the guided transitions of ES and iPS cells toward a ( cell fate to make potentially patient-specific ( cells available for transplantation.