The physical and molecular mechanisms of intestinal villus morphogenesis and repair

肠绒毛形态发生和修复的物理和分子机制

• 批准号: 10157985
• 负责人: Zev Jordan Gartner
• 金额: $ 58.4万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10157985
• 关键词: Adult; Architecture; Area; Atomic Force Microscopy; Atrophic; Automobile Driving; Calcium Signaling; Celiac Disease; Cells; Clinical; Computer Models; Connexin 43; Data; Development; Embryo; Endothelin; Endothelin Receptor; Engineering; Epithelial; Epithelium; Erinaceidae; Fibroblasts; Fingers; Future; Gap Junctions; Genes; Genetic Transcription; Goals; Human; Impairment; Infection; Inflammatory; Injury; Intestines; Investigation; Malabsorption Syndromes; Maps; Measurement; Measures; Mechanics; Mediating; Mesenchymal; Mesenchyme; Modeling; Molecular; Morphogenesis; Morphology; Mus; Myosin Type II; Natural regeneration; Nonmuscle Myosin Type IIA; Nutrient; Outcome; Pathway interactions; Patients; Pattern; Phase; Physical condensation; Play; Population; Process; Proteins; Radiation induced damage; Resolution; Role; Scientist; Shapes; Signal Transduction; Site; Small Intestines; Smooth Muscle Actin Staining Method; Smooth Muscle Myocytes; Source; Stains; Surface; Testing; Tissue Engineering; Tissues; Villus; blebbistatin; cell motility; chemotherapy; design; driving force; experimental study; gastrointestinal; improved; in vivo regeneration; inhibitor/antagonist; interfacial; intestinal epithelium; intestinal villi; live cell microscopy; monolayer; non-muscle myosin; novel therapeutics; programs; radiation effect; reconstitution; regenerative; repaired; side effect; single-cell RNA sequencing; uptake

ABSTRACT Villi are finger-like projection that line the lumen of the small intestine. Villi play a critical role in nutrient uptake by increasing the intestinal absorptive surface area by several orders of magnitude. Loss of this absorptive surface through villus atrophy causes major digestive complications and nutrient malabsorption. Abnormalities in villi are found in many gastrointestinal maladies, such as inflammatory bowel and celiac diseases, and are also side effects of radiation, chemotherapy, and infection. Degenerated villi can sometimes fully reform, yet in other situations regeneration is impaired, resulting in persistent villus atrophy and patient suffering. Villi emerge during development from an initially flat intestinal surface. The mechanisms underlying villus formation and repair remain poorly described, and an understanding of these processes is essential to develop new therapies. The long term goal of this proposal is to build an understanding of the molecules and forces that sculpt the villus during development and regeneration so as to improve strategies for growing and regenerating the intestine for human patients. Recent data from our labs suggest that the mesenchyme plays a central role in sculpting the architecture of the villus. Specifically, our preliminary data implicate a specialized population of self- organizing sub-epithelial mesenchymal cells that condense immediately below the forming villus as the source of the physical forces necessary to pattern and fold the overlying epithelium into villi. We investigated the molecular mechanisms leading to condensation of these cells using single cell RNAseq and found they also express a unique transcriptional program. This program has an unusual overlap with genes regulating Ca2+ mediated contractility in smooth muscle cells but without expressing smooth muscle actin. We provide evidence that inhibition of key proteins in this program results in a loss of mesenchymal condensation and villus evagination. Guided by these preliminary data, we propose to test two hypotheses related to the complementary physical and molecular aspects of villus formation. We combine quantitative measurements and computational modeling to test the hypothesis that the formation of villus condensates occurs analogously to phase separation phenomena studied extensively by physicists and material scientists, and that condensates exert physical forces on the overlying epithelium initiating its folding. We then test the hypothesis that Endothelin released from the epithelium triggers increased calcium signaling in the subepithelial mesenchyme, which are synchronized through gap junctions to drive cell contractility leading to phase separation and condensation. This project has major implications for our fundamental understanding of the developmental of the gut and for tissue engineering of intestinal tissue, as we do not know how mammalian intestinal villi are built. Thus, these findings will be impactful because they provide a new mechanistic blueprint for this process that incorporates both signals and forces. These findings will also lay the groundwork for future studies of regeneration: we find that in adults, the sub-epithelial mesenchyme retains expression of many of these molecular features. Further, these features are upregulated following injury.

抽象的 绒毛是小肠管腔的类似手指的投影。 Villi在养分吸收中起关键作用 通过将肠吸收表面积增加几个数量级。失去这种吸收性 通过绒毛萎缩的表面会导致重大的消化并发症和营养吸收不良。异常 在绒毛中，在许多胃肠道疾病中发现了炎症性肠病和腹腔疾病，并且是 也是放射线，化学疗法和感染的副作用。堕落的绒毛有时可以完全改革，但 其他情况的再生也受到损害，导致持续的绒毛萎缩和患者痛苦。 绒毛从最初的肠表面发育中出现。绒毛下的机制 形成和维修的描述仍然很差，对这些过程的理解对于发展至关重要 新疗法。该提议的长期目标是建立对分子和力量的理解 在开发和再生过程中雕刻绒毛，以改善增长和再生的策略 人类患者的肠道。我们实验室的最新数据表明，间充质在 雕刻绒毛的建筑。具体而言，我们的初步数据暗示了自我的专业人群 组织上皮下间充质细胞，这些细胞紧接在形成绒毛以下作为来源 将上皮上皮形成并将上皮折叠成绒毛所需的物理力。我们调查了 使用单细胞RNASEQ导致这些细胞凝结的分子机制，发现它们也 表达独特的转录程序。该程序与调节Ca2+的基因有着不同寻常的重叠 介导平滑肌细胞的收缩力，但没有表达平滑肌肌动蛋白。我们提供证据 在该程序中抑制关键蛋白的抑制导致间充质凝结和绒毛的损失 逃脱。在这些初步数据的指导下，我们建议检验两个与互补有关的假设 绒毛形成的物理和分子方面。我们结合了定量测量和计算 建模以检验绒毛的形成与相分离类似的假设 现象由物理学家和物质科学家进行了广泛的研究，凝结会发挥物理力量 在上皮上的上皮上，引发其折叠。然后，我们检验了内皮素从 上皮触发增加了上皮下间质的钙信号传导，该钙是同步的 通过间隙连接驱动细胞收缩力，导致相位分离和冷凝。 该项目对我们对肠道发展和对 肠道组织的组织工程，因为我们不知道如何建造哺乳动物肠绒毛。因此，这些 调查结果将具有影响力，因为它们为此过程提供了新的机械蓝图 信号和力量。这些发现还将为未来的再生研究奠定基础：我们发现 在成年人中，上皮下质质保留了许多这些分子特征的表达。更远， 受伤后这些特征被上调。