Genetic Regulation of Progenitor Cells in Appendicular Skeletal Development

附肢骨骼发育中祖细胞的遗传调控

• 批准号: 9251238
• 负责人: Yasuhiko Kawakami
• 金额: $ 32.3万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2018-09-11
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9251238
• 关键词: Anterior; Cartilage; Cell Cycle; Cell Lineage; Cell Proliferation; Cells; Congenital Abnormality; Congenital Limb Deformities; Cyclin-Dependent Kinase Inhibitor; Cyclin-Dependent Kinase Inhibitor Gene; Cyclin-Dependent Kinases; Cyclins; Data; Defect; Development; Differentiation and Growth; Digit structure; Disease; Distal; Elements; Embryo; Embryonic Development; Event; Femur; Fibroblast Growth Factor; Forelimb; Generations; Genes; Genetic; Genetic Counseling; Genetic Programming; Goals; Growth; Health; Hindlimb; Homeodomain Proteins; Homologous Gene; Human; Injury; Knowledge; Lateral; Limb Bud; Limb Development; Limb structure; Live Birth; Location; Mesenchyme; Mesoderm; Modeling; Molecular; Molecular Abnormality; Morphogenesis; Operating System; Pathway interactions; Phenotype; Positioning Attribute; Process; Proteins; Publications; Regulation; Shapes; Signal Transduction; Skeletal Development; Skeletal system; Skeleton; Stem cells; Structure; System; Testing; Tissues; Tretinoin; Up-Regulation; Zinc Fingers; beta catenin; bone; fibula; gene function; notochord; novel; progenitor; public health relevance; repaired; skeletal; skeletogenesis; tibia

DESCRIPTION (provided by applicant): The appendicular skeletal system represents a paradigm for development of skeletal elements with unique shapes and locations. Moreover, this system provides a platform to study how bone/cartilage in the same position develops into distinct shapes in two types of limbs, namely the forelimbs and hindlimbs. Elucidating how these skeletal elements are generated from progenitor cells is crucial for understanding the development of the appendicular skeletal system. During embryonic development, "the posterior growth zone", the structure located at the posterior of the body, grows and posteriorly extends the body. This process, called the body extension, progressively generates progenitor cells for various tissues, including the lateral plate mesoderm (LPM). Cells in the LPM give rise to the limb bud mesenchyme, which expand and undergo region-specific growth and differentiation, leading to progressive morphogenesis of skeletal elements from the most proximal (stylopod) to the middle (zeugopod) and distal (autopod) region. We obtained preliminary data supporting the idea that genetic systems earlier than limb bud formation regulate generation and expansion of progenitor cells for subsequent development of the appendicular skeletons. Conditional inactivation of Sall4, which encodes a zinc finger containing protein, prior to limb outgrowth, resulted in the loss of proximal-anterior skeletal elements only in the hindlimb, such as the femur, tibia and anterior digits. We also obtained preliminary data, suggesting that cells expressing Isl1, encoding a LIM homeodomain protein, in the hindlimb-forming region contribute to the formation of posterior-distal skeletal elements in hindlimbs, such as fibula and posterior digits. These results suggest that genetic systems by Isl1 and Sall4 operate in the LPM and regulate hindlimb progenitor cells to develop into specific skeletal elements. Furthermore, our preliminary data suggest that, in an earlier, upstream event, combined function of Sall4 and its homolog, Sall1, regulates body extension to generate hindlimb progenitors. The goal of the proposal is to determine the genetic and molecular mechanisms of Sall4, Isl1 and Sall1 operating in progenitor cells. We will have three specific aims for this goal. Aim 1 will test the hypothesis that Sall4 regulates proliferation and survival of hindlimb progenitors through regulation of the cyclin-dependent kinase inhibitor genes. Aim 2 will test the hypothesis that distinct regulation of ss-catenin by Sall4 and Isl1 controls proliferation and/or survival of hindlmb progenitor cells. Aim 3 will test the hypothesis that the combined function of Sall1 and Sall4 controls the formation of the hindlimb progenitors in the LPM through regulation of body extension. Completion of this project will reveal a novel concept that genetic systems regulate the expansion of progenitors in the LPM for development of the appendicular skeletal system in later stages. Elucidating this novel mechanism that regulates appendicular skeletal development will significantly advance our current understanding of appendicular skeletogenesis

描述（由申请人提供）：附肢骨骼系统代表了具有独特形状和位置的骨骼元件的开发范例。此外，该系统提供了一个平台来研究同一位置的骨/软骨如何在两种类型的肢体（即前肢和后肢）中发育成不同的形状。阐明这些骨骼元素是如何从祖细胞产生的对于理解阑尾骨骼系统的发育至关重要。在胚胎发育过程中，“后生长区”（位于身体后部的结构）生长并向后延伸身体。这个过程称为身体延伸，逐渐产生各种组织的祖细胞，包括侧板中胚层 (LPM)。 LPM 中的细胞产生肢芽间充质，肢芽间充质扩张并经历区域特异性生长和分化，导致骨骼元素从最近端（茎足）到中间（zeugopod）和远端（自足）区域的渐进形态发生。我们获得了初步数据，支持这样的观点：肢芽形成之前的遗传系统调节祖细胞的生成和扩张，以促进附肢骨骼的后续发育。在肢体生长之前，编码含锌指蛋白的 Sall4 有条件失活，仅导致后肢近端前部骨骼元件的损失，例如股骨、胫骨和前指。我们还获得了初步数据，表明后肢形成区域中表达 Isl1（编码 LIM 同源域蛋白）的细胞有助于后肢后远端骨骼元件（例如腓骨和后指）的形成。这些结果表明 Isl1 和 Sall4 的遗传系统在 LPM 中运作并调节后肢祖细胞发育成特定的骨骼元件。此外，我们的初步数据表明，在更早的上游事件中，Sall4 及其同源物 Sall1 的组合功能调节身体伸展以产生后肢祖细胞。该提案的目标是确定 Sall4、Isl1 和 Sall1 在祖细胞中运作的遗传和分子机制。为了实现这一目标，我们将制定三个具体目标。目标 1 将检验 Sall4 通过调节细胞周期蛋白依赖性激酶抑制剂基因来调节后肢祖细胞的增殖和存活的假设。目标 2 将检验以下假设：Sall4 和 Isl1 对 ss-catenin 的不同调节控制后肢祖细胞的增殖和/或存活。目标 3 将检验以下假设：Sall1 和 Sall4 的联合功能通过调节身体伸展来控制 LPM 中后肢祖细胞的形成。该项目的完成将揭示一个新概念，即遗传系统调节 LPM 中祖细胞的扩张，以促进附肢骨骼系统的后期发育。阐明这种调节四肢骨骼发育的新机制将显着推进我们目前对四肢骨骼发生的理解