Sex steroid signaling and adaptive growth of the intestine

项目总结 性特异性类固醇激素控制着包括卵巢在内的生殖器官中细胞的生长和增殖， 乳房、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(如结直肠癌和胃癌)的性别偏见发病率、生理影响 非性器官上的类固醇信号可能与健康有着深远的关系。我们发现， 果蝇类固醇激素，20-羟基蜕皮激素(20HE)，促进肠道干细胞(ISC)增殖和 适应器官的生长，导致雌蝇交配后的肠道几乎扩大了一倍(4)。他是 由交配后激活的卵巢产生，并通过其受体ECR/USP和 下游的目标是远大和Eip75B。20HE还通过未知的机制触发EGFR/ERK信号，以及 这对于ISC激活至关重要。我们的数据表明，依赖20HE的女性肠道重塑增强 营养吸收、繁殖力和生殖适合性。然而，ISCs的20HE依赖的过度活动也 增加女性肠道发育不良和肿瘤的易感性，这是一种健康的权衡，可以缩短 寿命。我们的发现提出了许多问题，关于20HE信号如何重新配置女性的肠道，这是如何 改变肠道和全身生理学，以及性类固醇是否在哺乳动物中扮演类似的角色。在这里，我们解决了 这些问题有四个具体目的。首先，我们使用针对细胞类型的遗传学来确定ECR的功能 ISCs和称为成肠母细胞(EB)的承诺前体细胞中的信号转导，重点关注20HE基因如何靶向 激活ISC的生长、新陈代谢和分裂，以及20HE如何扩大干细胞库。在目标2中，我们使用 进行单细胞RNA测序，以绘制体内20HE对五种主要肠道细胞类型的影响。我们也 用Cut&Tag进行体内ECR结合位点分析，定位中肠祖细胞中直接的20HE：ECR基因靶点 细胞。这些化验的综合数据将给出基因表达网络的全面图谱。 20HE信号在肠道中的作用。在目标3中，我们检验了20HE优化养分输送到 通过改变肠道的生长、代谢和/或消化能力来影响果蝇的其他器官(如卵巢、脂肪体) 肠道细胞。在目标4中，我们在小鼠肠道器官和小鼠身上进行了实验，测试了 人性性类固醇雌激素、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。这些研究将为性类固醇的作用提供洞察力 有丝分裂原，干细胞自我更新的调节者，新陈代谢和营养吸收的媒介。这项工作将 为理解许多人类性别偏见的发病基础提供范例和主导数据 疾病，特别是那些涉及干细胞行为改变的疾病，如癌症、慢性炎症、退行性疾病、 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.