Mechanochemical mechanisms of intestinal villus development and regeneration

肠绒毛发育和再生的机械化学机制

基本信息

批准号：
10231998
负责人：
Tyler Huycke
金额：
$ 6.6万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10231998
关键词：
Address Adult Architecture Area Atrophic Calcium Candidate Disease Gene Cells Coupled Cues Data Development Embryo Endothelin Engineering Epithelial Event Fingers Foundations Future Gap Junctions Genes Genetic Genetic Transcription Goals Hormones Human Impairment Injury Intestinal Diseases Intestines Link Malabsorption Syndromes Measurement Mechanics Mediating Mediator of activation protein Mesenchymal Mesenchyme Modeling Molecular Morphogenesis Morphology Mucous body substance Mus Natural regeneration Nutrient Pathway interactions Phase Physical condensation Process Regulation Reporter Resolution Role Shapes Signal Transduction Site Small Intestines Structure Surface Testing Tissues Villus experimental study functional restoration gastrointestinal improved in vivo intercellular communication interfacial intestinal villi irradiation mechanical force molecular marker monolayer new therapeutic target non-muscle myosin nutrient absorption physical property programs regenerative response single-cell RNA sequencing smoothened signaling pathway

项目摘要

PROJECT SUMMARY Intestinal villi comprise a mesenchymal core ensheathed by an epithelial layer that together increase the intestinal absorptive surface area nearly 100 fold. Damage to villi incurred by irradiation, chemotherapeutics, and many gastrointestinal maladies cause villus atrophy, resulting in nutrient malabsorption and digestive complications. Remarkably, in many cases atrophied villi fully regenerate to restore their finger-like morphology, yet in other situations the regenerative process is impaired, resulting in persistent villus atrophy. How villi regenerate their morphology and why this process can fail are unknown. Moreover, we lack an understanding of how mammalian villi are initially built during development. The long-term goal of this project is to understand how signals and forces are integrated to sculpt mammalian villi during development and regeneration so as to improve strategies for growing and regenerating human intestinal tissue. Villus formation initiates in the embryo with the aggregation of mesenchymal cells adjacent to the overlying epithelium that form condensations, termed villus clusters. While villus clusters seem to be required for villus morphogenesis, the mechanisms underlying their formation have not been identified. Here, I explore a link between these events that first build villi in the mammalian embryo during development and those that rebuild them in the adult during regeneration. First, I quantify the physical properties of villus clusters and test whether mesenchymal condensation into clusters, and the subsequent buckling of the epithelium into villi, is initiated through mesenchymal cellular contractility and reinforced by differential interfacial tension. Next, I examine the genetic mechanisms underlying the mechanics of these mesenchymal condensation events and villus formation. Specifically, I put forth and test a model generated from single-cell RNA sequencing data wherein the contractile activities of the subepithelial mesenchyme are triggered by Endothelin-dependent Ca2+ signaling, and the contractions become coupled locally between neighboring cells through gap junctions to drive cluster formation and epithelial buckling. Finally, I test whether subepithelial mesenchymal cells utilize similar mechanochemical mechanisms to regenerate villus architecture in response to damage in the adult intestine, and additionally, characterize villus regeneration at single cell resolution to identify new genetic mediators of adult villus architecture. Together, these studies will define how signals and forces interact to form and reform mammalian intestinal villi, identify new therapeutic targets to stimulate villus regeneration, and, more broadly, will address the question of how tissue shape and size are regenerated.

项目概要肠绒毛由一个被上皮层包裹的间充质核心组成，这些上皮层共同增加了肠道吸收表面积近100倍。放射线、化疗和药物引起的绒毛损伤许多胃肠道疾病会导致绒毛萎缩，导致营养吸收不良和消化不良并发症。值得注意的是，在许多情况下，萎缩的绒毛完全再生，恢复其手指状形态，然而在其他情况下，再生过程受到损害，导致绒毛持续萎缩。绒毛如何再生它们的形态以及为什么这个过程会失败尚不清楚。此外，我们还缺乏了解哺乳动物绒毛在发育过程中最初是如何形成的。该项目的长期目标是了解如何在发育和再生过程中，信号和力量被整合来塑造哺乳动物绒毛，从而改善生长和再生人类肠道组织的策略。绒毛的形成在胚胎中开始，伴随着与上覆绒毛相邻的间充质细胞的聚集形成凝结的上皮细胞，称为绒毛簇。虽然绒毛簇似乎是绒毛所必需的形态发生，其形成的机制尚未确定。在这里，我探索一个链接在哺乳动物胚胎发育过程中首先构建绒毛的这些事件和重建绒毛的事件之间它们在成人再生过程中。首先，我量化绒毛簇的物理特性并测试是否间充质凝结成簇，随后上皮屈曲成绒毛，开始通过间充质细胞的收缩性并通过不同的界面张力得到加强。接下来，我检查这些间充质凝结事件和绒毛形成机制的遗传机制。具体来说，我提出并测试了一个由单细胞 RNA 测序数据生成的模型，其中收缩上皮下间质的活性由内皮素依赖性 Ca2+ 信号传导触发，并且收缩通过间隙连接在相邻细胞之间局部耦合以驱动簇形成和上皮屈曲。最后，我测试上皮下间充质细胞是否利用类似的机械化学响应成人肠道损伤而再生绒毛结构的机制，此外，以单细胞分辨率表征绒毛再生，以确定成年绒毛的新遗传介质建筑学。这些研究将共同定义信号和力量如何相互作用来形成和改造哺乳动物肠绒毛，确定刺激绒毛再生的新治疗靶点，并且更广泛地说，将解决组织形状和大小如何再生的问题。