Cellular Basis of Incisor Asymmetry

项目摘要 形态发生是细胞、组织和器官获得形状的生物学过程， 它们在胚胎发育过程中的功能，并且可以在组织再生过程中重新利用， 在成熟的有机体中。对胚胎移植的研究表明， 形态学和机械细胞-细胞相互作用，都由信号分子控制，可能会驱动组织- 包括对称鼠磨牙在内的多种上皮组织中的特定形状。然而，更深层次的 了解调节形态发生的基本原理和细胞行为， 这些过程用于未来的再生疗法，可以减轻衰老和疾病的影响。 我将利用小鼠门牙的早期发育阶段来研究细胞行为如何驱动定向生长 和形态发生。小鼠切牙的发育是高度不对称的，调节这种不对称的机制 这一进程仍然难以捉摸。先前的研究表明，在声波刺猬（Shh）信号的扰动 导致异常的切牙形态，Shh依赖的细胞运动驱动牙芽内陷， 对称的臼齿通过这一提议，我将检验Shh信号的调制 级联驱动细胞形态和行为的变化，决定了不对称的形态发生 门齿的发展。我将测量和量化局部细胞和组织形态学变化， 如细胞形状、核位置和牙齿曲率，以及动态细胞行为，如微分 增殖，定向细胞分裂和细胞嵌入，使用高分辨率实时成像和我们的新 软件程序，玛格丽塔。这将建立一个细胞形态和行为的基础图谱 负责上皮弯曲事件，驱动不对称切牙的早期发育（目的1）。下一个是 切牙外植体中Shh信号的药理学干扰和Shh的时空调节 基因突变体中的表达将决定该信号转导途径的调节程度 影响切牙发育过程中的细胞形态（目的2）。这些发现将提供重要的见解 进入基础牙齿和发育生物学，这有可能应用于未来的牙科 再生疗法目前修复缺失牙列的策略（即，种植体、假牙）可能导致 显著的骨吸收或可能由于有限的骨整合而失败。因此，生物再生牙齿使用 形态发生驱动的技术具有显著改善牙科修复的潜力。 这些研究目标将与一个全面的培训计划一起进行， 我的牙医科学家生涯培训包括来自两个高素质赞助商的结构化指导， 以及通过会议、研讨会、期刊俱乐部和加州大学旧金山分校的课程进行科学和技术培训， 提供优秀的研究环境和优秀的牙科临床培训学校。

Project Summary Morphogenesis is the biological process by which cells, tissues, and organs acquire the shape that is critical to their function during embryonic development, and it can be repurposed during regeneration of tissues after damage in a mature organism. Work on embryonic explants has revealed that differences in cellular morphologies and mechanical cell-cell interactions, both controlled by signaling molecules, likely drive tissue- specific shapes in multiple epithelial tissues including the symmetric murine molar. Nevertheless, a deeper understanding of the basic principles and cellular behaviors that regulate morphogenesis is required to leverage these processes for future regenerative therapies that can mitigate the effects of aging and disease. I will use the early developmental stages of the murine incisor to study how cell behaviors drive directional growth and morphogenesis. Murine incisor development is highly asymmetric, and the mechanisms regulating this process have remained elusive. Prior studies have shown that perturbations in Sonic Hedgehog (Shh) signaling result in abnormal incisor morphology, and that Shh-dependent cell movement drives tooth bud invagination in the symmetrical molar. Through this proposal, I will test the hypothesis that modulation of the Shh signaling cascade drives changes in cellular morphology and behavior that determine the asymmetric morphogenic development of the incisor. I will measure and quantify localized cellular and tissue morphological changes such as cell shape, nuclear position, and tooth curvature, as well as dynamic cell behaviors such as differential proliferation, oriented cell division, and cell intercalation, using high resolution live imaging and our novel software program, MARGARITA. This will establish a foundational atlas of cell morphologies and behaviors responsible for the epithelial bending events driving early development of the asymmetric incisor (Aim 1). Next, pharmacological perturbation of Shh signaling in incisor explants and spatiotemporal modulation of Shh expression in genetic mutants will determine to what extent the modulation of this signal transduction pathway affects cellular morphology during incisor development (Aim 2). These findings will provide significant insights into basic tooth and developmental biology, which have the potential to be applied towards future dental regenerative therapies. Current strategies to restore missing dentition (i.e., implants, dentures) can lead to significant bone resorption or may fail due to limited osseointegration. Thus, biologically regenerating teeth using morphogenesis-driven techniques has the potential to significantly improve restorative dentistry. These research goals will be conducted in conjunction with a comprehensive training plan designed to develop my career as a dentist-scientist. Training includes structured mentorship from two highly qualified sponsors, as well as scientific and technical training through meetings, seminars, journal clubs, and classes at UCSF, which offers both an outstanding research environment and an excellent dental school for clinical training.