ABSTRACT
Organoids are intricate 3D conglomerations of self-organized cells that bear cellular and structural resemblance to organs. Also coined "mini-organs," organoids are able to recapitulate different aspects of the organ environment, making them more biologically relevant in vitro model systems compared to their predecessors, which are monolayer cell cultures. Because of the complex nature of the human lungs, studying respiratory biology, lung development, organ homeostasis, and regeneration, as well as lung diseases in vitro, has been a daunting task. However, over the past few years, efforts have been made to generate lung organoids that are composed of major lung epithelial cell types from various cell sources. This has opened avenues to not just better model diseases, but to scrutinizing molecular and cellular mechanisms underlying lung development, regeneration, and repair. Other pertinent applications of lung organoids include understanding disease pathogenesis, facilitating drug discovery, and therapeutic testing. The field of pulmonary research has benefitted tremendously from the advent of human lung organoids. However, the current lung organoid models are far from perfect; it is imperative to address current limitations to enhance the reliability, reproducibility, and biological fidelity of the human lung organoid systems.
