Multi-modal Atlas of Self-organized Mucociliary Patterning

组织由多种细胞类型组成，这些细胞类型必须保持平衡并以定型模式排列，以实现生理器官功能。在发育、稳态和再生中，这种精确的编排依赖于自组织机制，该机制整合了由基因调控网络控制的细胞命运选择和细胞/组织水平的形态发生运动。这在内部器官（例如气道上皮）中固有地难以研究。胚胎爪蟾表皮作为一个很好的范例，揭示脊椎动物粘膜纤毛组织图案的保守原则。在稳定状态下，表皮由两个细胞层组成，一个是干细胞基底层，一个是含有分泌细胞的浅表上皮层，分泌细胞调节离子稳态，产生粘液和抗菌肽，以及均匀间隔的多纤毛细胞，形成>100根运动纤毛，这些纤毛同步跳动并产生细胞外液流以清除粘液和病原体-这一过程称为粘液纤毛清除。精确的细胞类型比例在表皮的不同区域是不适应的，我们假设这是为了优化有机体的粘膜纤毛功能。在MAP项目中，我们希望通过将系统和单细胞转录组学与活细胞成像相结合，将该模型提升到一个新的水平，以识别构建成熟粘膜纤毛表皮所需的全部细胞类型和细胞行为。我们的目标是确定用于产生和适应粘膜纤毛细胞类型的组成/组织在胚胎表皮的分子机制，通过分析信号和形态发生的贡献模式的形成。具体而言，我们将：（1.）建立一个详细的形态学，转录组和整个胚胎的粘液纤毛细胞类型的分子图谱。（2.）使用新的荧光报告分子通过活细胞成像研究所有粘液纤毛细胞类型的行为。（3.）解决Scf/Kit粘附/排斥系统在产生纤毛和分泌细胞的可变分布中的作用。（4.）通过结合数学模型和实验操作，阐明在规格和转分化过程中信号传导对最终粘液纤毛组织图案化的功能作用。该项目的宏伟目标将通过Walentek和Kodjabachian实验室的联合实现，这些实验室在非洲爪蟾系统生物学，信号研究和实时成像方面拥有丰富的专业知识。该项目将使我们能够以前所未有的时空分辨率研究组织范围内的图案，并阐明脊椎动物组织发育中图案形成的保守原则。更好地了解体内调节粘液纤毛细胞类型组成的机制将成为理解生理适应并最终改善气道疾病诊断和治疗的基础。

Tissues are composed of multiple cell types that must be kept in balance and arranged in stereotyped patterns for the emergence of physiological organ function. In development, homeostasis and regeneration, such precise choreography depends on self-organized mechanisms that integrate cell fate choices, controlled by gene regulatory networks, and cell-/tissue-level morphogenetic movements. This is inherently difficult to study in internal organs, e.g. the airway epithelium. The embryonic Xenopus epidermis serves as an excellent paradigm to uncover conserved principles of vertebrate mucociliary tissue patterning. At steady-state, the epidermis is composed of two cell layers, a basal layer of stem cells, and a superficial epithelial layer containing secretory cells, which regulate ion homeostasis, produce mucus and antimicrobial peptides, and evenly spaced multiciliated cells forming >100 motile cilia that beat synchronously and produce extracellular fluid flow to remove mucus and pathogens – a process called mucociliary clearance. The precise cell type proportions are variably adapted in different regions of the epidermis, and we postulate that this is to optimize organismal mucociliary function. In the MAP project, we wish to bring this model to the next level by combining systems and single cell transcriptomics with live cell imaging to identify the entire complement of cell types and cell behaviors necessary to build the mature mucociliary epidermis. We aim to determine the molecular mechanisms that are used to generate and adapt mucociliary cell type composition/organization in the embryonic epidermis by analyzing both signaling and morphogenetic contributions to pattern formation. Specifically, we will: (1.) Establish a detailed morphological, transcriptomic and molecular map of mucociliary cell types over the entire embryo. (2.) Use new fluorescent reporters to study the behavior of all mucociliary cell types by live cell imaging. (3.) Address the role of the Scf/Kit adhesion/repulsion system in generating variable distributions of ciliated and secretory cells. (4.) Elucidate the functional role of signaling on final mucociliary tissue patterning by combining mathematical models and experimental manipulations, during specification and in trans-differentiation. The ambitious goals of this project will be reached through the association of the Walentek and Kodjabachian labs, which hold great expertise in Xenopus systems biology, signaling studies and live imaging. This project will allow us to investigate tissue-wide patterning with unprecedented spatiotemporal resolution, and elucidate conserved principles of pattern formation in vertebrate tissue development. Gaining a better understanding of the mechanisms that regulate mucociliary cell type composition in vivo will form the basis to understand physiological adaptations and to eventually improve diagnosis and treatment of airway diseases.