Programs of Gene Expression in Olfactory Neurogenesis

描述（由申请人提供）：神经系统中神经元多样性的产生需要大量细胞谱系的规范和分化。连续的发育程序控制着单个神经元类型的产生、细胞迁移、轴突延伸，并最终形成功能性突触连接。成熟神经元从其祖细胞分化的特定遗传程序仍未完全确定，部分原因是难以在其天然环境中研究神经元祖细胞。在脊椎动物的嗅觉系统中，初级感觉神经元通过多能神经祖细胞的增殖和分化在整个成年期不断再生。这一特点使得嗅觉系统特别适合研究神经干细胞的特性。虽然嗅觉谱系的不同阶段已经被一组有限的分子标记所确定，但在发育和再生过程中定义和调节嗅觉神经发生的遗传程序仍有待了解。到目前为止，对调控多能嗅觉祖细胞（谱系中最早的细胞）的转录网络一无所知。阐明这些调控网络对于理解成熟的神经元和非神经元细胞类型是如何从嗅觉上皮成体组织干细胞中产生的至关重要。在这个应用中，我们建议研究转录因子p63 -肿瘤抑制因子p53家族的成员-在嗅觉干细胞调节中的作用。通过全基因组转录组分析和基因功能缺失分析，我们最近发现p63在体内是嗅觉干细胞自我更新和分化的关键调节因子，类似于它在其他上皮干细胞中的作用。本文拟探讨p63在嗅觉干细胞中的细胞和分子作用。具体来说，我们将(1)确定p63在自我更新和分化之间的选择中的作用；(2)确定p63及其相关家族成员p53是否相互作用调控嗅觉干细胞动力学；(3)通过鉴定p63的下游靶点，表征p63依赖性的嗅觉干细胞调控转录网络。这些研究将共同阐明调节嗅觉干细胞维持、增殖和分化的细胞和分子机制。此外，我们的研究将为理解其他神经干细胞类型的调节机制提供一个模型，并为未来治疗和治疗方法的发展奠定基础，以改善神经组织损伤和变性。

DESCRIPTION (provided by applicant): The generation of neuronal diversity in the nervous system requires the specification and differentiation of a multitude of cellular lineages. Successive developmental programs control the generation of individual neuronal types, cell migration, axon extension, and ultimately the formation of functional synaptic connections. The specific genetic programs underlying the differentiation of mature neurons from their progenitors remain incompletely characterized, in part because of the difficulty in studying neuronal progenitor cells in their native environments. In the vertebrate olfactory system, primary sensory neurons are continuously regenerated throughout adult life via the proliferation and differentiation of multipotent neural progenitor cells. This feature makes the olfactory system particularly amenable for studies on the properties of neuronal stem cells. While distinct stages of the olfactory lineage have been identified with a limited set of molecular markers, much remains to be learned about the genetic programs that both define and regulate olfactory neurogenesis during development and regeneration. To date, nothing is known about the transcriptional networks regulating the multipotent olfactory progenitors, the earliest cells in the lineage. Elucidation of these regulatory networks is critical for understanding how mature neuronal and non-neuronal cell types are generated from the adult tissue stem cell of the olfactory epithelium. In this application we propose to investigate the role of the transcription factor p63 - a member of the p53 family of tumor suppressors - in olfactory stem cell regulation. Through whole genome transcriptome profiling and genetic loss-of-function analysis, we recently discovered that p63 is a key regulator of olfactory stem cell self-renewal and differentiation in vivo, similar to its established role in other epithelial stem cells. Here we propose to investigate the cellular and molecular actions of p63 in the olfactory stem cell. Specifically, we will (1) determine the role of p63 in the choice between self-renewal and differentiation; (2) determine whether p63 and its related family member p53 interact to regulate olfactory stem cell dynamics; and (3) characterize the p63-dependent transcriptional network regulating the olfactory stem cell by identifying the downstream targets of p63. Together these investigations will illuminate the cellular and molecular mechanisms regulating olfactory stem cell maintenance, proliferation and differentiation. Moreover, our studies will provide a model for understanding the mechanisms regulating other neural stem cell types and lay the groundwork for the future development of treatments and therapeutics to ameliorate neural tissue damage and degeneration. PUBLIC HEALTH RELEVANCE: The proposed research will define and characterize the genetic interactions regulating neurogenesis and tissue regeneration in the olfactory epithelium. This information is critical for an understanding of the causes of degenerative diseases and injuries resulting from the misregulation of these processes, and will lay the foundation for future strategies aimed at ameliorating neurodegenerative disorders and traumatic injuries by identifying new therapeutic targets and potential cell replacement therapies.