Figure 6. Lung organoids possess abundant distal bipotent progenitor cells.
(A) The expression of the distal progenitor marker SOX9 remained unchanged over time and expression of the AECI marker PDPN was low in HLO cultures. (B) The majority of SFTPC+ cells (green, left panel) co-expressed SOX9 (red). Similarly, many cells expressing the AECI early marker HOPX+ (green, right panel) co-expressed SOX9 (red). Few, scattered cells expressed the late AECII marker SFTPB (white, second panel) or the AECI marker, PDPN (third panel, white). Few PDPN+ cells also showed elongated, squamous morphology seen in the adult lung. (C) Human lung AECII cells labeled with SFTPC (green, left panel) did not co-express SOX9. SFTPB+ cells (white, second panel) in the adult human lung have similar morphology to SFTPB+ cells in HLOs. Human lung AECI cells expressed PDPN (white, third panel), and show characteristic AECI cell shape. Human AECI cells express HOPX (green, right panel), but did not co-express SOX9. (B–C) Scale bar in lower magnification images in B (upper panel) represent 50 µM and the scale bars in higher magnification images in B, C (lower panel) represent 10 µM. (D) D50 HLOs contain lamellar bodies which are organelles specific to AECII cells. Scale bars represent 500 nm.
Figure 6—figure supplement 1. SFTPC+ cells express lung specific markers.
