Sex steroid signaling and adaptive growth of the intestine

项目摘要 性别特异性类固醇激素控制生殖器官（包括卵巢）中的细胞生长和增殖， 乳腺、子宫、前列腺和睾丸。但它们如何影响非生殖器官却鲜为人知。考虑 许多常见疾病（如结肠直肠癌和胃癌）的性别偏见发病率， 类固醇信号在非性器官上的作用可能具有深远的健康相关性。我们发现 果蝇类固醇激素，20-羟基-蜕皮激素（20 HE），促进肠干细胞（ISC）增殖， 适应性器官生长，导致雌性果蝇的肠道在交配后几乎翻了一番（4）。20他是 由交配后激活的卵巢产生，并通过其受体EcR/Usp刺激ISC增殖， 下游靶向Broad和Eip75B。20HE还通过未知机制触发EGFR/ERK信号传导， 这对于ISC激活是必要的。我们的数据表明，女性的20HE依赖性肠道重塑增强了 营养吸收、繁殖力和生殖适合度。然而，20HE依赖的ISC活动过度也 增加了女性肠道发育不良和肿瘤发生的倾向，这是一种健康的权衡， 寿命我们的研究结果提出了许多问题，关于20HE信号如何重新配置女性肠道， 改变肠道和全身生理机能，以及性类固醇是否在哺乳动物中发挥类似作用。在这里， 这些问题有四个具体目标。首先，我们使用细胞类型靶向遗传学来确定EcR的功能 ISCs和称为肠母细胞（EB）的定向祖细胞中的信号传导，重点关注20HE基因如何靶向 激活ISC的生长，代谢和分裂，以及20HE如何扩大干细胞库。在目标2中，我们使用 单细胞RNA测序以绘制20HE对体内五种主要肠细胞类型中的每一种的影响。我们也 通过CUT & Tag进行体内EcR结合位点分析，以定位中肠祖细胞中的直接20HE：EcR基因靶点 细胞这些分析的综合数据将给出基因表达网络的综合图谱 20HE信号在肠道中的作用。在目标3中，我们测试了20HE优化营养输送到 通过改变肠道的生长、代谢和/或消化能力， 肠细胞在目标4中，我们在小鼠肠道类器官和小鼠中进行实验，测试是否存在 人性类固醇雌二醇、孕酮和/或睾酮促进肠上皮细胞（IEC） 哺乳动物的繁殖和肠道生长。这些研究将提供深入了解性类固醇的作用， 有丝分裂原、干细胞自我更新的调节剂以及代谢和营养吸收的介质。这项工作将 为了解许多人类性别偏见发生率的基础提供范例和领先数据。 疾病，特别是涉及改变的干细胞行为的疾病，如癌症，慢性炎症，退行性， 和代谢性疾病。

PROJECT SUMMARY Sex-specific steroid hormones control cell growth and proliferation in reproductive organs including the ovaries, breast, uterus, prostate and testes. But how they impact non-reproductive organs is less well known. Considering the sex-biased incidence of many common diseases (e.g. colorectal and gastric cancer), the physiological effects of steroid signaling on the non-sex organs probably have profound health-relevance. We discovered that the Drosophila steroid hormone, 20-hydroxy-ecdysone (20HE), promotes intestinal stem cell (ISC) proliferation and adaptive organ growth, causing the female fly’s intestine to nearly double in size after mating (4). 20HE is produced by the activated ovaries after mating, and stimulates ISC proliferation via its receptor EcR/Usp and downstream targets Broad and Eip75B. 20HE also triggers EGFR/ERK signaling via unknown mechanisms, and this is essential for ISC activation. Our data suggest that 20HE-dependent gut remodeling in females enhances nutrient uptake, fecundity and reproductive fitness. However, the 20HE-dependent hyperactivity of ISCs also increases the female predisposition to gut dysplasia and tumorigenesis, a fitness trade off that can shorten lifespan. Our findings raise many questions about how 20HE signaling re-configures the female gut, how this alters gut and whole-body physiology, and whether sex steroids play similar roles in mammals. Here we address these questions in four Specific Aims. First, we use cell type-targeted genetics to determine the functions of EcR signaling in ISCs and committed progenitors called enteroblasts (EB), focusing on how 20HE gene targets activate ISC growth, metabolism and division, and on how 20HE amplifies the stem cell pool. In Aim 2, we use single cell RNA sequencing to map the effects of 20HE on each of the five main gut cell types in vivo. We also perform in vivo EcR binding site analysis by CUT&Tag, to map direct 20HE:EcR gene targets in midgut progenitor cells. The combined data from these assays will give a comprehensive atlas of the gene expression network effects of 20HE signaling in the gut. In Aim 3 we test the hypothesis that 20HE optimizes nutrient delivery to the fly’s other organs (e.g. ovaries, fat body) by altering the growth, metabolism and/or digestive capabilities of gut enterocytes. In Aim 4, we conduct experiments in mouse intestinal organoids and mice, testing whether the human sex steroids estradiol, progesterone, and/or testosterone promote intestinal epithelial cell (IEC) proliferation and gut growth in mammals. These studies will provide insights into the action of sex steroids as mitogens, regulators of stem cell self-renewal, and mediators of metabolism and nutrient uptake. This work will provide paradigms and lead data for understanding the basis of the sex-biased incidence of many human diseases, notably those involving altered stem cell behavior such as cancer, chronic inflammation, degenerative, and metabolic diseases.