Understanding adult stem cell-niche interactions using the Drosophila intestine

成体肠道干细胞（ISCs）在维持我们的肠道中起着关键作用，干细胞的失调是癌症等疾病的主要原因之一。一个未充分研究的机制是周围上皮细胞的作用和它们作为干细胞的小生境的功能，并且其信号促进或抑制ISC增殖。了解ISC微环境的作用将有助于我们更好地了解健康和患病组织中成体干细胞的调节。果蝇肠道是研究ISC的一种经济有效且遗传学上易于处理的模型。果蝇的肠道，像它的哺乳动物同行，是由一群肠干细胞（ISCs）分裂和维持肠上皮细胞。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。与哺乳动物相似，EGFR/Ras通路组分的过表达与负Wnt通路调节因子APC的丧失组合将导致肿瘤生长。Vivan Therapeutics一直在使用果蝇系统来测试不同药物组合对定制的结直肠癌患者头像的影响，这些患者头像具有与患者相同的驱动突变。他们的平台允许对不同的药物组合和/或遗传操作进行高通量生存性筛选。在这个项目中，我们将分别操纵干细胞过度生长和周围的上皮细胞，以解决周围上皮细胞作为ISC增殖的小生境的作用。与Vivan Therapeutics合作，我们将通过并行操纵不同的生长促进途径来构建ISC过度生长的模型。我们将联合收割机结合下调周围分化的肠上皮细胞（EC）和内分泌细胞（EE）的候选基因，以确定新的生态位因子，加剧或抑制ISC过度生长。我们采用了一个集中的清单分泌的分子，在这些细胞类型的肠中表达，并检查敲低或过表达的影响，增强或抑制ISC过度生长。我们将使用Vivan自动化生存平台进行筛选。将在果蝇肠道以及人类肠道类器官培养物中对选定的候选物进行体内随访，以确定其作用模式

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