Regulation of Stem Cell Self-Renewal and Differentiation

 描述(申请人提供)：干细胞自我更新和分化的调节NIH 1 R01 GM080501成体干细胞在一生中需要补充分化的细胞和修复受损的组织。在成人干细胞谱系中调节自我更新和分化开始的机制是再生医学以及理解癌症的起源和生物学的关键。我们建议研究与躯体支持细胞伙伴的相互作用如何调节果蝇雄性生殖系干细胞谱系中自我更新和分化的决定，这是一个在体内根据来自当地环境的信号来研究成体干细胞的强大系统。在之前的资助周期中，我们发现睾丸中的体细胞囊细胞在功能上等同于哺乳动物的Sertoli细胞，提供了一个关键的微环境，调节从生殖系干细胞到过渡放大精原细胞的转换。我们现在建议利用我们已经建立的强大的系统和工具来研究调节这种关键状态转变的分子电路 雄性生殖系干细胞谱系对来自体细胞支持细胞的提示做出反应。为了发现维持早期生殖细胞处于自我更新或启动分化状态以响应其微环境的内在因素，我们将测试从生物信息学分析中提出的转录调控电路模型，该模型来自对生殖系干细胞成为TA精原细胞时协调上调的基因的生物信息学分析，包括bHLH转录因子Criterless及其抑制剂EMC，以及锌指转录因子Klu(神经母细胞系干细胞状态的调节因子)、阻遏物AEF-1和激活剂ROUND。为了阐明囊细胞是否以及如何发出“GO分化”信号来指示生殖系干细胞退出自我更新并进入有限的传递扩增(TA)分裂的精原计划，我们将鉴定并研究编码预测分泌或细胞表面蛋白的基因的作用，这些蛋白在体细胞囊细胞中是早期生殖细胞正确启动分化所必需的，首先是Gp150，一种Notch通路信号的调节因子，在我们的细胞类型特异性RNI筛选的最初几轮中被发现。我们的结果可能会阐明干细胞生态位的另一种观点，即分化信号在其中扮演关键角色，并将阐明近距离相互作用的细胞-细胞信号如何协调不同类型的细胞的共分化，这些细胞类型必须共同作用才能形成功能组织。

 DESCRIPTION (provided by applicant): Regulation of Stem Cell Self-renewal and Differentiation NIH 1 R01 GM080501 Adult stem cells are required throughout life to replenish differentiated cells and repair damaged tissue. The mechanisms that regulate self-renewal vs onset of differentiation in adult stem cell lineages are key for regenerative medicine as well as understanding the genesis and biology of cancer. We propose to investigate how interactions with somatic support cell partners regulate the decision between self renewal and differentiation in the Drosophila male germ line stem cell lineage, a powerful system for study of adult stem cells in vivo in the context of signals from their local environment. In previous funding cycles, w discovered that somatic cyst cells in the testis, functionally equivalent to mammalian Sertoli cells, provide a crucial microenvironment that regulates the switch from germ line stem cell to transit amplifying spermatogonia. We now propose to utilize the powerful system and tools we have established to investigate the molecular circuitry that regulates this key state transition in the male germ line stem cell lineage in response to cues from somatic support cells. To discover the intrinsic factors that maintain early germ cells in a state to either self-renew or initiate differentiation in response to their microenvironment, we will test models for transcriptional regulatory circuitry suggested from bioinformatic analysis of genes coordinately upregulated as germ line stem cells become TA spermatogonia, including the possible roles of the bHLH transcription factor Daughterless and its inhibitor Emc, and the Zn finger transcription factor Klu a regulator of stem cell state in neuroblast lineages, the repressor Aef-1, and the activator rotund. To elucidate whether and how cyst cells send a "go differentiate" signal to instruct germ line stem cells to exit self-renewal and enter the spermatogonial program of limited transit amplifying (TA) divisions, we will identify and investigate the role of genes encoding predicted secreted or cell surface proteins that are required in somatic cyst cells for early germ cells to properly initiate differentiation as transit amplifying spermatogonia, starting with Gp150, a regulator of Notch pathway signaling, identified in the initial rounds of our cell type specific RNi screen. Our results may elucidate an alternative view of the stem cell niche, in which differentiation signals play key roles, and will illuminate how close-range reciprocal cell-cell signaling can coordinate co-differentiation of disparate cell types that must work together to make functional tissues.