Sex steroid signaling and adaptive growth of the intestine

项目概要 性别特异性类固醇激素控制生殖器官（包括卵巢）的细胞生长和增殖， 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。考虑到 许多常见疾病（例如结直肠癌和胃癌）的性别偏向发病率、生理效应 非性器官上的类固醇信号传导可能与健康具有深远的相关性。我们发现 果蝇类固醇激素 20-羟基蜕皮激素 (20HE) 可促进肠干细胞 (ISC) 增殖和 适应性器官生长，导致雌性果蝇的肠道在交配后几乎增大一倍 (4)。 20HE 是 交配后由激活的卵巢产生，并通过其受体 EcR/Usp 刺激 ISC 增殖 下游目标为 Broad 和 Eip75B。 20HE 还通过未知机制触发 EGFR/ERK 信号传导，并且 这对于 ISC 激活至关重要。我们的数据表明，女性中 20HE 依赖性肠道重塑增强 营养吸收、繁殖力和生殖适应性。然而，ISC 的 20HE 依赖性过度活跃也 增加女性肠道发育不良和肿瘤发生的倾向，这是一种可以缩短肠道发育不良和肿瘤发生的健康权衡 寿命。我们的研究结果提出了许多关于 20HE 信号如何重新配置女性肠道的问题，这如何 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的作用。在这里我们解决 这些问题体现在四个具体目标中。首先，我们使用细胞类型靶向遗传学来确定 EcR 的功能 ISC 和称为肠母细胞 (EB) 的定型祖细胞中的信号传导，重点关注 20HE 基因如何靶向 激活 ISC 生长、代谢和分裂，以及 20HE 如何放大干细胞库。在目标 2 中，我们使用 单细胞 RNA 测序，绘制 20HE 对体内五种主要肠道细胞类型的影响。我们也 通过 CUT&Tag 进行体内 EcR 结合位点分析，以绘制中肠祖细胞中的直接 20HE:EcR 基因靶标 细胞。这些测定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，我们测试了以下假设：20HE 优化了营养物质输送到 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（例如卵巢、脂肪体） 肠细胞。在目标 4 中，我们在小鼠肠道类器官和小鼠身上进行了实验，测试是否 人类性类固醇雌二醇、黄体酮和/或睾酮促进肠上皮细胞 (IEC) 哺乳动物的增殖和肠道生长。这些研究将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调节剂。这项工作将 为理解许多人类性别偏见发病率的基础提供范式和主要数据 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、退行性变、 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.