The mature lung in both humans and mice is highly vascularized, with approximately 30% of all cells being endothelial cells (ECs). The blood vessels have a physiological role in gas exchange within the tissue, but the vascular cells have additional role(s) beyond supplying oxygen and nutrients to the tissue.  For example, the adult lung endothelium responds to injury by activating pathways for alveolar re epithelialization and during embryonic development, disrupting vascularization ex vivo affects the stereotypical pattern of airway branching, consistent with a perfusion-independent crosstalk between the endothelium and epithelium. Today’s guests explore the molecular contribution of ECs and pericytes to the differentiation of distal airway progenitor cells into mature alveolar epithelial cells and will discuss the broader role of the vascular system in the maturation and regeneration or the lung.