Chromatin regulation of epithelial stem cell function

上皮干细胞功能的染色质调节

• 批准号: 10448365
• 负责人: Adam David Gracz
• 金额: $ 38.67万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10448365
• 关键词: Address; Adopted; Adult; Aging; Biological Models; Cell Differentiation process; Cells; Cellular biology; Chromatin; Development; Disease; Enhancers; Enzymes; Epithelial; Equilibrium; Exhibits; Foundations; Genomics; Goals; Health; Homeostasis; Human; In Vitro; Infection; Inflammation; Informal Social Control; Injury; Intestines; Life; Malignant Neoplasms; Modeling; Natural regeneration; Property; Regenerative response; Regulation; Reporter; Research; Site; Tissues; Transgenes; Traumatic injury; adult stem cell; cell type; chromatin modification; epithelial stem cell; genomic locus; in vivo; interest; intestinal epithelium; mouse model; novel; progenitor; programs; regeneration following injury; response; self-renewal; stem cell differentiation; stem cell function; stem cells; stemness; tool; transcription factor; tumorigenesis

ABSTRACT Stemness is a functional cellular attribute defined by properties of multipotency (the ability to produce all differentiated cell types in a tissue) and self-renewal (the ability to produce new stem cells). In adult epithelial tissues, stemness can exist in: (1) dedicated stem cells occupying a defined niche, and (2) differentiated cells that exhibit plasticity to drive regeneration following injury. Stem cells must balance self-renewal with differentiation, and differentiated cells must balance lineage specific identity with plasticity to participate in regenerative responses. My lab is interested in understanding how chromatin modifications and their associated enzymes interact with site-specific transcription factors (TFs) to establish cell identities while simultaneously facilitating alternative cell fates. We focus on intestinal stem cells (ISCs), which drive the renewal of the intestinal epithelium approximately once a week throughout adult life, as a model system. Over the next five years, my research program will explore how TFs and chromatin modifying enzymes contribute to an exit from the stem cell state as ISC differentiate. Current models propose that rapid differentiation and plasticity in the intestinal epithelium is regulated by chromatin landscapes that are highly similar across all intestinal epithelial cell types, regardless of differentiation stage. Recent studies in my lab have challenged this model using a Sox9EGFP mouse model that allows us to isolate ISCs, progenitors, and differentiated cells with a single reporter transgene. We quantified changes in chromatin accessibility and 5-hydroxymethylcytosine and identified significant chromatin dynamics at genomic loci consistent with enhancers. Our analyses identified novel candidate TF-chromatin interactions and raise exciting questions about the importance of chromatin regulation in adult epithelial stem cells. Our future research will build on this progress to understand: (1) how stem cell- associated chromatin is decommissioned by TFs in differentiation, (2) how lineage-specific regulatory programs are “primed” in ISCs, and (3) how chromatin modifying enzymes bridge regulation of self-renewal and differentiation. The approach proposed here will establish a long-term research program, with broad potential to expand into studies of plasticity/de-differentiation, chromatin regulation of epithelial responses to environmental challenges, and development. Our goal is to pursue a basic mechanistic understanding of chromatin regulation in stemness that will have foundational relevance to human health and disease, including epithelial responses to inflammation, infection, injury, aging, and tumorigenesis.

抽象的 干性是一种功能性细胞属性，由多能性（产生所有物质的能力）定义 组织中分化的细胞类型）和自我更新（产生新干细胞的能力）。在成人上皮细胞中 组织中，干性可以存在于：(1) 占据特定生态位的专用干细胞​​，以及 (2) 分化细胞 表现出可塑性以驱动损伤后的再生。干细胞必须平衡自我更新 分化，分化的细胞必须平衡谱系特异性和可塑性才能参与 再生反应。我的实验室有兴趣了解染色质修饰及其相关的方式 酶与位点特异性转录因子 (TF) 相互作用以建立细胞身份，同时 促进细胞命运的改变。我们专注于肠道干细胞 (ISC)，它能驱动肠道的更新 作为模型系统，在整个成年过程中大约每周一次对上皮细胞进行检测。未来五年，我的 研究计划将探索转录因子和染色质修饰酶如何有助于退出 ISC 分化时的干细胞状态。当前的模型表明，快速分化和可塑性 肠上皮受到所有肠上皮高度相似的染色质景观的调节 细胞类型，无论分化阶段如何。我实验室最近的研究使用 Sox9EGFP 小鼠模型使我们能够用单个报告基因分离 ISC、祖细胞和分化细胞 转基因。我们量化了染色质可及性和 5-羟甲基胞嘧啶的变化，并确定了 基因组位点处显着的染色质动态与增强子一致。我们的分析发现新颖 候选 TF-染色质相互作用，并提出有关染色质调控重要性的令人兴奋的问题 在成体上皮干细胞中。我们未来的研究将建立在这一进展的基础上，以了解：（1）干细胞如何- 相关染色质在分化过程中被 TF 停用，(2) 谱系特异性调控程序如何 在 ISC 中“启动”，以及 (3) 染色质修饰酶如何桥接自我更新和 差异化。这里提出的方法将建立一个长期研究计划，具有广泛的潜力 扩展到可塑性/去分化、上皮对环境反应的染色质调节的研究 挑战与发展。我们的目标是追求对染色质调控的基本机制的理解 干性与人类健康和疾病具有基础相关性，包括上皮反应 炎症、感染、损伤、衰老和肿瘤发生。