The respiratory system, including the lungs, is essential for terrestrial life. While recent research has advanced our understanding of lung development, much still relies on animal models and transcriptome analyses. In this study conducted within the Human Developmental Cell Atlas (HDCA) initiative, we describe the protein-level spatiotemporal organization of the lung during the first trimester of human gestation. Using high-parametric tissue imaging with a 30-plex antibody panel, we analyzed human lung samples from 6 to 13 post-conception weeks, generating data from over 2 million cells across five developmental timepoints. We present a resource detailing spatially resolved cell type composition of the developing human lung, including proliferative states, immune cell patterns, spatial arrangement traits, and their temporal evolution. This represents an extensive single-cell resolved protein-level examination of the developing human lung and provides a valuable resource for further research into the developmental roots of human respiratory health and disease.

Sountoulidis et al. provide a spatial gene expression atlas of human embryonic lung during the first trimester of gestation and identify 83 cell identities corresponding to stable cell types or transitional states. The lung contains numerous specialized cell types with distinct roles in tissue function and integrity. To clarify the origins and mechanisms generating cell heterogeneity, we created a comprehensive topographic atlas of early human lung development. Here we report 83 cell states and several spatially resolved developmental trajectories and predict cell interactions within defined tissue niches. We integrated single-cell RNA sequencing and spatially resolved transcriptomics into a web-based, open platform for interactive exploration. We show distinct gene expression programmes, accompanying sequential events of cell differentiation and maturation of the secretory and neuroendocrine cell types in proximal epithelium. We define the origin of airway fibroblasts associated with airway smooth muscle in bronchovascular bundles and describe a trajectory of Schwann cell progenitors to intrinsic parasympathetic neurons controlling bronchoconstriction. Our atlas provides a rich resource for further research and a reference for defining deviations from homeostatic and repair mechanisms leading to pulmonary diseases.

Multiplexed antibody-based imaging enables the detailed characterization of molecular and cellular organization in tissues. Advances in the field now allow high-parameter data collection (>60 targets); however, considerable expertise and capital are needed to construct the antibody panels employed by these methods. Organ mapping antibody panels are community-validated resources that save time and money, increase reproducibility, accelerate discovery and support the construction of a Human Reference Atlas.

The respiratory system, encompassing the lungs, trachea, and vasculature, is essential for terrestrial life. Although recent research has illuminated aspects of lung development, such as cell lineage origins and their molecular drivers, much of our knowledge is still based on animal models, or is deduced from transcriptome analyses. In this study, conducted within the Human Developmental Cell Atlas (HDCA) initiative, we describe the spatiotemporal organization of lung during the first trimester of human gestation in situ and at protein level. We used high-parametric tissue imaging on human lung samples, aged 6 to 13 post-conception weeks, using a 30-plex antibody panel. Our approach yielded over 2 million individual lung cells across five developmental timepoints, with an in-depth analysis of nearly 1 million cells. We present a spatially resolved cell type composition of the developing human lung, with a particular emphasis on their proliferative states, spatial arrangement traits, and their temporal evolution throughout lung development. We also offer new insights into the emerging patterns of immune cells during lung development. To the best of our knowledge, this study is the most extensive protein-level examination of the developing human lung. The generated dataset is a valuable resource for further research into the developmental roots of human respiratory health and disease.