Understanding and manipulating morphogenetic processes to generate in vitro models of airways.

Branching morphogenesis, the process by which cells and tissues organize into complex branched tubular structures, is fundamental to the development of functional organs, including the respiratory airways in mammalian lungs. Advances in understanding the molecular and cellular mechanisms driving morphogenetic processes have enabled the development of sophisticated in vitro models that mimic the structure and function of airways. This review recapitulates developmental principles guiding airway morphogenesis, including the key signaling pathways, cellular interactions, and the different biochemical and mechanical cues. We discuss how these principles have been harnessed to engineer in vitro models of airways, providing a comprehensive overview of current artificial lung culture systems. We consider fully morphogenetic-mimicking strategies such as organoid modeling to more reductionist strategies, such as airway-on-chip systems. By examining both the breakthroughs and current limitations, we highlight the potential of these models to reproduce airway physiology and diseases, such as congenital pulmonary airway malformation and chronic obstructive pulmonary disease. Furthermore, we consider future directions in the field, emphasizing the need for controlling complex environmental cues and integrating multiple cellular components to create increasingly accurate and functional airway models.