Long-Term Engraftment Promotes Differentiation of Alveolar Epithelial Cells from Human Embryonic Stem Cell Derived Lung Organoids

Abstract

Human embryonic stem cell (hESC) derived 3D human lung organoids (HLOs) provide a promising model to study human lung development and disease. HLOs containing proximal or/and immature distal airway epithelial cells have been successfully generated in vitro, such as early staged alveolar type 2 (AT2) cells (SPC/SOX9) and immature alveolar type 1 (AT1) cells (HOPX/SOX9). When HLOs were transplanted into immunocompromised mice for further differentiation in vivo, only few distal epithelial cells could be observed. In this study, we transplanted different stages of HLOs into immunocompromised mice to assess whether HLOs could expand and mature in vivo. We found that short-term transplanted HLOs contained lung progenitor cells (NKX2.1, SOX9, and P63), but not SPC AT2 cells or AQP5 AT1 cells. Meanwhile, long-term engrafted HLOs could differentiate into lung distal bipotent progenitor cells (PDPN/SPC/SOX9), AT2 cells (SPC, SPB), and immature AT1 cells (PDPN, AQP5). However, HLOs at late in vitro stage turned into mature AT1-like cells (AQP5/SPB/SOX9) in vivo. Immunofluorescence staining and transmission electron microscopy (TEM) results revealed that transplanted HLOs contained mesenchymal cells (collagen I), vasculature (ACTA2), neuroendocrine-like cells (PGP9.5), and nerve fiber structures (myelin sheath structure). Together, these data reveal that hESC-derived HLOs would be useful for human lung development modeling, and transplanted HLOs could mimic lung organ-like structures in vivo by possessing vascular network and neuronal network.

Organoids as a Powerful Model for Respiratory Diseases

“…During mouse lung development, AT1 and AT2 cells are generated directly from a bipotent progenitor [10,11]. It remains to be determined whether or not a similar bipotent progenitor population exists in the human fetal lung; however, cells expressing both an AT2 cell marker (surfactant protein C (Sftpc)) and an AT1 cell marker (podoplanin) were observed in long-term cultured organoids derived from human embryonic stem cells [12]. In adults, AT2 cells were shown to give rise to AT1 cells;…”

Recapitulating idiopathic pulmonary fibrosis related alveolar epithelial dysfunction in a human iPSC‐derived air‐liquid interface model

“…Limited access to primary human ATII cells, particularly from diseased patients, and the rapid loss of ATII marker expression and function when cultured in vitro, make it challenging to study the role of human ATII cells in IPF 19 . Recent advances have led to the successful derivation of ATII‐like cells from human pluripotent stem cells (hPSCs, including both embryonic stem cells and induced pluripotent stem cells (iPSCs)), providing a promising alternative cell source for in vitro disease modeling 20‐26 . Previous reports on hPSC‐derived lung cells showed that despite their phenotypic similarities to mature lung epithelium, these models are equivalent to human fetal lung cells, rather than representing an adult state 27,28 .…”

Recapitulating idiopathic pulmonary fibrosis related alveolar epithelial dysfunction in an iPSC-derived air-liquid interface model

“…Limited access to primary human ATII cells, particularly from diseased patients, and the rapid loss of ATII marker expression and function when cultured in vitro, make it challenging to study the role of human ATII cells in IPF (19). Recent advances have led to the successful derivation of ATII-like cells from human pluripotent stem cells (hPSCs, including both embryonic stem cells and induced pluripotent stem cells), providing a promising alternative cell source for in vitro disease modeling (20)(21)(22)(23)(24)(25)(26). Previous reports on hPSC-derived lung cells showed that despite their phenotypic similarities to mature lung epithelium, these models are equivalent to human fetal lung cells, rather than representing an adult state (27,28).…”