Table 1.

Overview of cells relevant for alveologenesis

Name of cell	Name of progenitor cell	Localization of cell	Function of cell for alveologenesis	Interaction with other cells
Alveolar epithelial cell type I (AEC I)	Bipotent progenitor (Sftpc+, Pdpn+) [1]	Epithelium	Providing the majority of alveolar surface area	AEC II (during regeneration) [16]
Alveolar epithelial cell type II (AEC II)	Bipotent progenitor (Sftpc+, Pdpn+) [1]	Epithelium, close proximity to lipofibroblast	Surfactant production, transdifferentiation to AEC I after lung injury [16]	Formation and maintenance of Lipofibroblast via Pthrp (parathyroid hormone-related protein)/Pparg (peroxisome proliferator-activated receptor gamma) signaling pathway [35, 37]
Alveolar myofibroblast	Alveolar myofibroblast progenitor; Pdgfra + LIF (to be validated) [25]	Mesenchyme, Tip of growing secondary septae	Deposition of Elastin in the apex of secondary septae and secondary septae formation [30, 55]	Not known
Lipofibroblast	Fgf10+ mesenchymal cell [32, 33]	Mesenchyme, close proximity to AEC II	Secretion of triglycerides and leptin for AEC II [37] postnatal niche for AEC II [34]	AEC II [35, 37], epithelium (Pdgfa) [31]
Endothelial cell	Endothelial progenitor cell (hemangioblasts)	Subepithelial mesenchyme (SEM)	Angio-/vasculogenesis important for alveologenesis [47]	Epithelium [43, 45]