Understanding adult stem cell-niche interactions using the Drosophila intestine

成体肠道干细胞（ISCs）在肠道的维持中起着至关重要的作用，干细胞的失调是癌症等疾病的主要原因之一。一个未被充分研究的机制是周围上皮细胞的作用及其作为干细胞的生态位的功能，以及促进或抑制ISC增殖的信号。了解ISC微环境的作用将有助于我们更好地了解成体干细胞在健康和病变组织中的调控作用。果蝇肠道是研究ISCs的一种具有成本效益和遗传可移植性的模型。果蝇的肠道，像哺乳动物一样，是由一群肠道干细胞（ISCs）维持的，它们分裂并维持肠上皮。控制ISC分裂和分化的主要信号通路在果蝇和哺乳动物之间是保守的。与哺乳动物类似，EGFR/Ras通路组分的过表达与负wnt通路调节因子APC的缺失将导致肿瘤的生长。Vivan Therapeutics公司一直在使用果蝇系统来测试不同药物组合对定制的大肠癌患者化身的影响，这些患者体内含有与患者相同的驱动突变。他们的平台允许对不同药物组合和/或基因操作进行高通量生存能力筛选。在这个项目中，我们将分别操纵干细胞过度生长和周围上皮，以解决周围上皮作为ISC增殖的生态位的作用。在与Vivan Therapeutics的合作中，我们将通过并行操纵不同的生长促进途径来建立ISC过度生长的模型。我们将结合周围分化肠细胞（EC）和内分泌细胞（EE）中候选基因的下调，以确定加剧或抑制ISC过度生长的新生态位因子。我们使用了在这些细胞类型的肠道中表达的分泌分子的重点列表，并检查了敲低或过表达对增强或抑制ISC过度生长的影响。我们将使用Vivan自动生存能力平台进行筛选。选定的候选药物将在果蝇肠道和人类肠道类器官培养中进行体内随访，以确定它们的作用模式

Adult intestinal stem cells (ISCs) play a critical role in the maintenance of our intestine and dysregulation of stem cells is one of the main causes of diseases such as cancer. An understudied mechanism is the role of the surrounding epithelial cells and their function as a niche for the stem cells and which signals either promote or inhibit ISC proliferation. Understanding the role of the ISC micro-environment will help us better understand the regulation of adult stem cells in both healthy and diseased tissues. The Drosophila intestine has been a cost-effective and genetically tractable model for studying ISCs. The Drosophila intestine, like its mammalian counterparts, is maintained by a population of Intestinal Stem Cells (ISCs) that divide and maintain the intestinal epithelium. Major signaling pathways controlling ISC division and differentiation are conserved between flies and mammals. Similar to mammals, overexpression of the EGFR/Ras pathway components combination with loss of the negative Wnt-pathway regulator APC will lead to tumorous outgrowths. Vivan Therapeutics has been using the Drosophila system to test the effect of different drug combinations on custom-built colorectal cancer patient avatars harboring the same driver mutations as seen in the patient. Their platform allows for high-throughput survivability screening of different drug combinations and/or genetic manipulations. In this project we will separately manipulate stem cell overgrowth and the surrounding epithelium to address the role of the surrounding epithelium as a niche for ISC proliferation. In collaboration with Vivan Therapeutics, we will build models for ISC overgrowth by manipulating different growth-promoting pathways in parallel. We will combine this with downregulation of candidate genes in the surrounding differentiated enterocytes (EC) and endocrine cells (EE) to identify novel niche factors that exacerbate or inhibit ISC overgrowth. We employ a focused list of secreted molecules that are expressed in the intestine in these cell types and check the effect of knockdown or overexpression for enhancement or suppression of ISC overgrowth. We will use the Vivan automated survivability platform for the screening. Selected candidates will be followed up in vivo in both the Drosophila intestine as well as human intestinal organoid culture to determine their mode of action