Creation of adult epithelial stem cells from differentiated epithelial

描述（由申请人提供）：近年来，许多注意力集中在使用胚胎干（ES）细胞及其分化后代再生各种成体组织的前景上。然而，我们相信，在可预见的未来，至少在上皮组织的情况下，一个更可行和可实现的策略将来自于旨在诱导分化的成体细胞重编程为定向祖细胞和干细胞的实验方案，然后可以作为老化或各种病理过程耗尽的成体组织再生的载体。为此，我们打算开发一种可应用于分化的上皮细胞的信号传导剂的鸡尾酒，以便将它们重编程为谱系定向的上皮干细胞。我们的策略是重新激活一个潜在的发育程序，称为上皮-间充质转化（EMT）。我们以前已经表明，诱导成EMT赋予分化的乳腺上皮细胞许多与上皮干细胞相关的性状。重要的是，我们相信我们的理论适用于广泛的分化上皮细胞，包括复层鳞状上皮，如口腔粘膜。EMT在胚胎发育的各个步骤中影响关键的形态发生步骤。一般来说，研究集中在EMT将细胞命运从上皮细胞转变为间充质细胞的能力上，从而引起细胞形态和功能的深刻变化。然而，我们最近的研究结果表明，EMTs在干细胞自我更新，从而在组织内稳态的一种新的生理作用。加强EMT产物和干细胞状态之间的这种关联是发现假定的人类和小鼠乳腺干细胞已被证明具有间充质性状，进一步将EMT与干细胞生物学联系起来。重要的是，EMT和干细胞状态之间的密切相似之处似乎不是乳腺上皮的特异性：新出现的证据表明，EMT诱导转录因子（TF）蜗牛和蛞蝓在皮肤形态发生中起着重要作用。在发育过程中，上皮-间充质转化（EMT）由个体细胞从相邻细胞层接收的背景信号诱导和协调。因此，胚胎上皮细胞上的几种旁分泌信号的会聚诱导该上皮细胞经历EMT。基于这些观察结果，我们假设细胞内EMT程序的初始触发取决于该细胞由一组定义的此类旁分泌信号的伴随刺激，并且所得间充质/干细胞状态的维持随后取决于涉及先前触发进入EMT的相同因子的自分泌信号循环的激活。事实上，我们的初步数据与该模型一致，强调了细胞外信号环境对调节EMT的重要性，并加强了我们的理论基础，以开发一种实验方案，将信号传导剂的混合物作为去分化和重编程分化的上皮细胞至干细胞样状态的手段。从长远来看，我们打算开发一种方案，用于诱导许多不同的成体上皮细胞类型控制去分化为相应的干细胞。这样的方案具有产生大量定向上皮干细胞的潜力，所述定向上皮干细胞有望再生各种耗尽的成体上皮组织。 公共卫生相关性：近年来，人们的注意力集中在利用胚胎干细胞（ES）再生各种成体组织的前景上。然而，我们相信，在可预见的未来，一个更加可行和可实现的策略将来自于旨在诱导分化的成体细胞重编程为定向祖细胞和干细胞的实验方案。这些重新编程的细胞可以作为再生的载体，用于再生因衰老或各种病理过程而耗尽的成年组织。为此，我们打算开发一种信号传导剂的混合物，其可以应用于分化的上皮细胞的体外培养物，以便通过激活潜在的发育程序将它们重编程为定向上皮干细胞。我们相信，这种策略可以应用于许多上皮组织，如皮肤或口腔粘膜。

DESCRIPTION (provided by applicant): Much attention has focused in recent years on the promise of using embryonic stem (ES) cells and their differentiated progeny to regenerate various adult tissues. We believe, however, that for the foreseeable future, a far more viable and attainable strategy will derive, at least in the case of epithelial tissues, from experimental protocols designed to induce the reprogramming of differentiated adult cells into committed progenitors and stem cells, which can then serve as vehicles for the regeneration of adult tissues depleted by aging or by various pathological processes. For this purpose, we intend to develop a cocktail of signaling agents that can be applied to differentiated epithelial cells in order to reprogram them to lineage-committed epithelial stem cells. Our strategy is to re-activate a latent developmental program, termed the Epithelial-Mesenchymal Transition (EMT). We have previously shown that induction into EMT confers on differentiated mammary epithelial cells many of the traits associated with epithelial stem cells. Importantly, we believe that our rationale is applicable to a wide range of differentiated epithelial cells, including stratified squamous epithelia, such as the mucosa of the mouth. EMTs effect key morphogenetic steps during various steps of embryonic development. In general, research has focused on the ability of EMTs to switch cellular fate from epithelial to mesenchymal, thereby causing profound changes in cell morphology and function. However, our recent findings indicate a novel physiological role for EMTs in stem-cell self-renewal and thus in tissue homeostasis. Reinforcing this association between the products of EMT and the stem-cell state is the finding that putative human and mouse mammary stem cells have been shown to possess mesenchymal traits, further linking EMT to stem cell biology. Importantly, the close parallels between EMT and the stem-cell state do not appear to be an idiosyncrasy of the mammary epithelium: emerging evidence suggests an essential role for the EMT-inducing Transcription Factors (TF) Snail and Slug in skin morphogenesis. During the course of development, epithelial-mesenchymal transitions (EMTs) are induced and coordinated by contextual signals received by individual cells from adjacent cell layers. Thus, the convergence of several paracrine signals on an embryonic epithelial cell induces that epithelial cell to undergo an EMT. Based on these observations, we have hypothesized that the initial triggering of an EMT program within a cell depends on concomitant stimulation of that cell by a defined set of such paracrine signals, and that maintenance of the resulting mesenchymal/stem-cell state depends subsequently on the activation of autocrine signaling loops involving the same factors that previously triggered entrance into the EMT. Indeed, our preliminary data are in concordance with this model, underscoring the importance of the extracellular signaling environment for regulating EMTs, and reinforcing our rationale to develop an experimental protocol with a cocktail of signaling agents as a means to dedifferentiate and reprogram differentiated epithelial cells to a stem cell-like state. In the longer term, we intend to develop a protocol for inducing the controlled dedifferentiation of a number of distinct adult epithelial cell types into their corresponding stem cells. Such protocols have the potential of generating large numbers of committed epithelial stem cells that hold promise for the regeneration of a variety of depleted adult epithelial tissues. PUBLIC HEALTH RELEVANCE: Much attention has focused in recent years on the promise of using embryonic stem (ES) cells to regenerate various adult tissues. We believe, however, that for the foreseeable future, a far more viable and attainable strategy will derive from experimental protocols designed to induce the reprogramming of differentiated adult cells into committed progenitors and stem cells. These reprogrammed cells can then serve as vehicles for the regeneration of adult tissues depleted by aging or by various pathological processes. For this purpose, we intend to develop a cocktail of signaling agents that can be applied to in vitro cultures of differentiated epithelial cells in order to reprogram them to committed epithelial stem cells via activation of a latent developmental program. We believe that this strategy can be applied to many epithelial tissues, such as the skin or mouth mucosa.