Photoresponsive materials to study matricellular signaling dynamics during crypt formation and fission

摘要 小肠内衬单层上皮细胞，组织成隐窝-绒毛单位。这些上皮 细胞执行多种功能，例如帮助消化、营养吸收和充当屏障，但这些细胞 这些过程也会损害上皮层。因此，位于隐窝基部附近的肠干细胞（ISCs）被称为肠干细胞。 负责所有肠细胞类型的不断更新和快速补充，但隐窝本身也 需要通过一个叫做裂变的过程来维持。当一个肠隐窝分裂， 产生一个新的子隐窝，这对维持整体隐窝密度和肠道健康至关重要。尽管 隐窝分裂在损伤诱导的隐窝再生中的重要作用及其在肠道疾病中的错误调节（例如， 炎症性肠病），关于隐窝分裂如何启动的机制知之甚少，进展通过 隐窝分叉，并在不同的病理生理条件下进行调节。因此，拟议的研究旨在利用 光响应性水凝胶用于肠类器官的培养，然后开发出一个强大的和可预测的体外模型 地穴裂变事件的证据我们的创新材料和还原方法将使我们能够精确地调整 ISC定位并理解上皮细胞和ECM信号传导如何促进隐窝形成和分裂。我们将 测试与隐窝细胞和基质细胞信号传导的作用及其对类器官对称性破缺的影响有关的假设， 隐窝形成、隐窝分裂和对局部组织损伤的潜在代偿性细胞反应。我们特别 目标是：1.研究时空变化的细胞基质对肠类器官中真实的时间隐窝形成的作用。 2.迭代模式化肠类器官负载水凝胶以研究ECM相互作用在引导隐窝分裂中的作用。 和3.时空调控隐窝细胞组成，探讨其在隐窝分裂中的作用。

ABSTRACT The small intestine is lined with a single layer of epithelial cells that is organized into crypt-villus units. These epithelial cells perform multiple functions, such as aiding in digestion, nutrient absorbance, and serving as a barrier, but these processes also damage the epithelial layer. As a result, intestinal stem cell (ISCs) located near the base of crypts are responsible for the constant renewal and rapid replenishment of all intestinal cell types, but the crypts themselves also require maintenance through a process called fission. Crypt fission occurs when a single intestinal crypt divides and generates a new daughter crypt, which is essential for maintaining overall crypt density and intestinal health. Despite the important role of crypt fission in injury-induced crypt regeneration and its mis-regulation in intestinal diseases (e.g., inflammatory bowel disease), little is known about the mechanisms of how crypt fission is initiated, progresses through crypt bifurcation, and is regulated under different pathophysiological conditions. Thus, the proposed research aims to use photoresponsive hydrogels for the culture of intestinal organoids and then develop a robust and predictable in vitro model of crypt fission events. Our innovative materials and reductionist approach will allow us to precisely tune the properties of the ISC niche and understand how epithelial cells and ECM signaling contribute to crypt formation and fission. We will test hypotheses related to the role of crypt cells and matricellular signaling and its effects on organoid symmetry breaking, crypt formation, crypt fission, and the potential compensatory cellular response to local tissue damage. Specifically, we aim to: 1. Investigate the role of spatiotemporally varying cell-matrix on real time crypt formation in intestinal organoids. 2. Iteratively pattern intestinal organoid-laden hydrogels to study the role of the ECM interactions in guiding crypt fission. and 3. Spatiotemporally regulate crypt cell composition to investigate its role in crypt fission.