14-3-3?? and epithelial differentiation in the eye and other tissues

14-3-3？？

• 批准号: 8093146
• 负责人: Qiutang Li
• 金额: $ 22.36万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8093146
• 关键词: Anterior; Apical; Binding Sites; Biological Models; Cadherins; Cell Count; Cell Cycle; Cell Cycle Arrest; Cell Cycle Regulation; Cell Differentiation process; Cells; Cellular Structures; Complex; Contact Inhibition; Cornea; Corneal Diseases; Corneal Intraepithelial Neoplasia; Cyclin E; Cytoplasm; Defect; Detection; Development; Ductal; Epithelial; Epithelial Cells; Epithelium; Eye; Eye Part; Future; Gene Expression; Generations; Genes; Genetic; Hair; Hair follicle structure; Histocompatibility Testing; Homeostasis; Individual; Intestines; Lead; Link; Malignant Neoplasms; Mediating; Microarray Analysis; Molecular; Mus; Mutate; Mutation; Normal tissue morphology; Obstruction; Pathologic; Pathway interactions; Phenotype; Phosphorylation; Phosphotransferases; Physiologic pulse; Process; Proliferating; Regulation; Research Design; Role; Series; Signal Pathway; Signal Transduction; Skin; Squamous cell carcinoma; Stem cells; Structure; TCF3 gene; Time; Tissues; Transcription Coactivator; Transgenes; Vision; base; blind; corneal epithelium; in vivo; insight; loss of function; meibomian gland; mouse model; mutant; notch protein; prevent; progenitor; programs; research study; stem cell population; transcription factor

DESCRIPTION (provided by applicant): Epithelial differentiation has been widely studied, and the process can be divided into two general steps: generation of proliferating progenitors from resident stem cells, and the subsequent arrest and differentiation of these progenitors. Oscillation of the transcription factor TCF3 between activator and repressor is key to both maintaining a resident stem cell population and generating pulses of progenitor cells for these stem cells. These progenitors proliferate to fill the tissue field, and then the Notch pathway triggers their cell cycle arrest and differentiation. Accordingly when Notch1 is mutated, progenitors in the cornea, meibomian gland and hair follicles fail to differentiate and they proliferate beyond the tissue fields leading to pathologic loss of function. The timing of Notch1 signal initiation in proliferating progenitors is critical to define the precise number of cells and thus tissue topology. Insight into to how Notch1 signaling is initiated in this process is only now emerging. Epithelial tissue fields are established by cell-cell contact inhibition as proliferating progenitors come in contact. Mutations in cell contact inhibition signaling lead to progenitor outgrowth beyond normal tissue fields (as with Notch1 mutation), loss of tissue function and ultimately cancer. But, how might onset of Notch1 signaling be linked to such cell-cell contact? Cadherin-initiated junctional complexes not only mediate apical polarity in epithelial cells, they also initiate a kinase cascade known as Hippo which phosphorylates a set of transcription factors that regulate both the cell cycle as well as differentiation programs. This phosphorylation provides a binding site for 14-3-3, which in turn sequesters the factors in an inactive form in the cytoplasm. Recent results demonstrate that mutations in components of the cell contact inhibition kinase cascade lead to loss of Notch 1 activity, and likewise we have found that mutation of 14-3-3s in this pathway also leads to loss of Notch1 expression. Taken together, such results imply that as progenitors expand in tissues, their eventual cell contact signals 14-3-3s -dependent expression of Notch1 thereby signaling arrest and differentiation. In support of this hypothesis, we have found that mutation of 14-3-3s in mice leads to accumulation of proliferating progenitor cells and a phenotype indistinguishable from that of Notch 1 in the cornea, hair follicle and ductal structures such as those in the meibomian gland. This loss of 14-3-3s or Notch1 causes severe corneal defects, ductal obstruction leading to loss of terminal ascini and abnormal hair follicles leading to hair loss. Importantly, we demonstrate that expression of activated Notch1 rescues the differentiation defect in 14-3-3s mutant epithelial progenitors in culture. Here, we propose a series of studies designed to further establish linkage between 14-3-3s and the Notch1 pathway in epithelial differentiation in the cornea, meibomian gland and hair follicles and to development mouse model systems which can be used as a basis for a future R01 proposal examining the molecular details of the pathway through which 14-3-3s and Notch1 regulate the onset of epithelial differentiation. PUBLIC HEALTH RELEVANCE: The integrity of the cornea, the most anterior part of the eye, is indispensable for vision, as evident by the facts that more than forty-five million individuals worldwide are bilaterally blind and another 135 million have severely impaired vision in both eyes because of the loss of corneal transparency. Our proposed experiments aim to uncover the essential role of 14-3-3s and the signaling network in controlling the corneal epithelial homeostasis. Our studies will elucidate the molecular mechanism underlying the corneal disease development such as corneal intraepithelial neoplasia and squamous cell carcinoma; and provide new strategies for detection and treatment.

描述（由申请人提供）：已广泛研究上皮分化，该过程可以分为两个一般步骤：从居民干细胞中产生增生的祖细胞，以及随后对这些祖细胞的停滞和分化。激活剂和阻遏物之间转录因子TCF3的振荡是维持驻留干细胞群体的关键，又是为这些干细胞生成祖细胞脉冲的脉冲。这些祖细胞扩散以填补组织场，然后凹槽途径触发了它们的细胞周期停滞和分化。因此，当Notch1被突变时，角膜中的祖细胞，Meibomian腺体和毛囊无法区分，它们超越了组织场，导致功能的病理丧失。增殖祖细胞中Notch1信号启动的时间对于定义细胞的精确数量至关重要。洞悉此过程中如何在此过程中启动Notch1信号传导。随着增殖祖细胞接触，通过细胞接触抑制建立上皮组织场。细胞接触抑制信号传导中的突变导致祖细胞出现在正常组织场（与Notch1突变一样），组织功能的丧失和最终导致癌症。但是，Notch1信号传导的发作如何与这种细胞电池接触相关联？钙粘蛋白引起的连接络合物不仅介导上皮细胞中的顶极性，还启动了称为河马的激酶级联反应，该级联磷酸化，该级别磷酸化了一组转录因子，这些转录因子既调节细胞周期又是分化程序。这种磷酸化为14-3-3提供了一个结合位点，进而将细胞质中不活动形式的因子隔离。最近的结果表明，细胞接触抑制激酶级联反应的成分突变导致Notch 1活性的损失，同样，我们发现该途径中14-3-3s的突变也导致Notch1表达丧失。综上所述，这种结果表明，随着祖细胞在组织中的扩展，其最终的细胞接触信号14-3-3s依赖性notch1的表达，从而信号传导停滞和分化。为了支持这一假设，我们发现小鼠中14-3-3的突变导致祖细胞增殖细胞的积累和与角膜，毛囊和导管结构（例如梅博莫利亚腺体中的凹槽1）无法区分的表型。这种14-3-3或Notch1的损失会导致严重的角膜缺陷，导管阻塞导致末端assini的损失和异常的毛囊导致脱发。重要的是，我们证明了活化的Notch1的表达挽救了培养物中14-3-3S突变体上皮祖细胞中的分化缺陷。在这里，我们提出了一系列研究，旨在进一步建立14-3-3s与Notch1途径之间的联系，以及角膜上皮分化的Notch1途径，以及开发鼠标模型系统，可以用作未来R01提案的基础，用于研究14-3-3s和Notch1的途径分子的分子细节，并将其用于EPITH的分子。 公共卫生相关性：角膜的完整性，是眼睛的前部，对于视觉而言是必不可少的，这是事实证明的，全世界超过4000万人是双侧盲人的，而另外1.35亿人在两种眼睛的眼中都严重损害了视力，因为角膜透明度的丧失。我们提出的实验旨在揭示14-3-3s和信号网络控制角膜上皮稳态方面的重要作用。我们的研究将阐明角膜疾病发育的基本机制，例如角膜上皮内肿瘤和鳞状细胞癌；并提供检测和治疗的新策略。