Understanding Pancreatic Progenitors for Diabetes Cell-Replacement Therapy

描述（由申请人提供）：糖尿病是一个不断升级的全球健康问题。1型糖尿病和2型糖尿病都会导致产生胰岛素的β细胞逐渐丧失。我们的长期目标是开发β细胞替代策略，以克服糖尿病患者的胰岛素缺乏症。为了实现这一目标，我们开发了一种新的，更安全的方法，使用化学品和遗传因子将患者成纤维细胞转化为诱导多能干细胞（iPSC）。这些iPSC可以分化成多能胰腺祖细胞，β细胞的前体，使用为人类胚胎干细胞（hESC）开发的方案。然而，我们对胰腺祖细胞的基本生物学的理解仍然是初步的，这在开发有效策略以扩增和进一步分化这些祖细胞用于治疗方面存在障碍。 从我们自己的研究和其他实验室的研究中出现的证据表明，胰腺祖细胞是异质的，可能由具有不同生理功能的亚群组成。然而，这些亚群之间的分子和功能差异知之甚少。目前尚不清楚发育中的胰腺中的哪个亚群能够产生功能性β细胞，以及特定亚群能够自我更新的程度。甚至更少的是知道的生理功能和自我更新的胰腺祖细胞从胚胎干细胞分化的属性。我们的目标是在本提案中解决这些关键问题。 我们假设体内胰腺祖细胞区室含有异质亚群：（i）负责产生所有三种胰腺谱系的共同多能胰腺祖细胞;和（ii）负责产生一种或两种特定胰腺谱系的不同谱系特异性祖细胞。基于这一假设，本提案的总体目标是定义胰腺祖细胞 亚群的分子特征和生理功能，以及确定自我更新的机制。我们预计，我们的研究将产生以下结果。目的1将揭示在胚胎发育和hESC分化培养过程中存在不同的胰腺祖细胞亚群。这将鉴定能够产生功能细胞的祖细胞亚群。目的2将鉴定用于富集适当祖细胞亚群以进一步分化成祖细胞的细胞表面标记物，并为祖细胞扩增的研究奠定基础。目的3将阐明不同祖细胞亚群的自我更新机制，这对于开发新的、有效的策略来扩增胰腺祖细胞用于β细胞替代疗法至关重要。此外，产生大量人类胰腺祖细胞的能力将为研究这些细胞的生物学提供一种新的方法，以补充小鼠遗传学方法。从广义上讲，拟议的研究将导致新的发现，以填补关键的 我们目前对人类胰腺发育的认识存在空白。 公共卫生相关性：从人类多能干细胞中产生功能性胰腺β细胞为糖尿病提供了一种有希望的治疗方法，糖尿病是一种因β细胞丢失而导致的日益严重的全球健康问题。然而，履行这一承诺的一个主要挑战在于， 胰腺祖细胞是在胚胎发育过程中产生成熟的胰岛素分泌β细胞的前体细胞。本研究的目标是使用干细胞和发育生物学相结合的方法来了解胰腺祖细胞亚型的分子特征，生理功能和自我更新特性，这将为开发有效的β细胞替代疗法的合理方法奠定基础。

DESCRIPTION (provided by applicant): Diabetes mellitus is an escalating global health problem. Both Type 1 and Type 2 diabetes lead to the gradual loss of insulin-producing beta cells. Our long-term goal is to develop beta cell replacement strategies to overcome the insulin deficiency in diabetic patients. To achieve this goal, we have developed novel, safer approaches to convert patient fibroblasts to induced pluripotent stem cells (iPSCs) using chemicals together with genetic factors. These iPSCs can be differentiated into multipotent pancreatic progenitors, the precursors to beta cells, using protocols developed for human embryonic stem cells (hESCs). However, our understanding of the basic biology of pancreatic progenitor cells is still rudimentary, which presents hurdles in the development of effective strategies to expand and further differentiate these progenitor cells for therapy. Evidence emerged from our own studies and from those of other laboratories suggests that pancreatic progenitor cells are heterogeneous, and likely consist of subpopulations with different physiological functions. Yet, molecular and functional distinctions between these subpopulations are poorly understood. It is unclear which subpopulation(s) in the developing pancreas is(are) capable of generating functional beta cells, and to which extent a specific subpopulation is capable of self-renewal. Even less is known about the physiological functions and self-renewal properties of pancreatic progenitor cells differentiated from hESCs. We aim to address these critical questions in this proposal. We hypothesize that the pancreatic progenitor cell compartment in vivo contains heterogeneous subpopulations: (i) a common multipotent pancreatic progenitor responsible for generating all three pancreatic lineages; and (ii) distinct lineage-specific progenitors responsible for generating one or two specific pancreatic lineages. Based on this hypothesis, the overall objective of this proposal is to define pancreatic progenitor subpopulations in terms of their molecular characteristics and physiological functions, as well as to identify mechanisms for self-renewal. We anticipate that our study will yield the following outcomes. Aim 1 will reveal the presence of distinct pancreatic progenitor subpopulations both during embryo development and in hESC differentiation culture. This will identify the progenitor subpopulation(s) capable of generating functional cells. Aim 2 will identify cell surface markers for enrichment of the appropriate progenitor subpopulation(s) for further ¿ differentiation into ¿ cells, and set the stage for studies on expansion of progenitor cells. Aim 3 will elucidate the mechanism of self-renewal of distinct progenitor subpopulations, which are critical for the development of novel, effective strategies to expand pancreatic progenitors for beta cell replacement therapy. Additionally, the ability to generate a large quantity of human pancreatic progenitor cells will provide a new way to study the biology of these cells to complement mouse genetics approaches. Broadly, the proposed research will lead to novel findings to fill in critical gaps in our current knowledge of human pancreatic development. PUBLIC HEALTH RELEVANCE: Generating functional pancreatic beta cells from human pluripotent stem cells offers a promising cure for diabetes, a growing global health problem resulting from the loss of beta cells. However, a major challenge in fulfilling such a promise lies in the rudimentary understanding of the distinct types of pancreatic progenitor cells, which are the precursors that generate mature, insulin-secreting beta cells during embryo development. The goal of this research is to use combined stem cell and developmental biology approaches to understand pancreatic progenitor subtypes in terms of their molecular characteristics, physiological functions, and self-renewal properties, which will form the foundation for developing rational approaches to effective beta cell replacement therapy.