Lung Progenitor Research Articles

Abstract 2156: Lung niche factors for progenitor cell self-renewal sustain lung cancer stem cells and contribute to drug resistance to kinase inhibitors in non-small cell lung cancer

Abstract A mechanism underlying anti-cancer drug resistance relies on the existence of cancer stem cells (CSCs). However, CSCs are either absent or are few in number in xenograft tumors and syngeneic mouse models. We developed new lung cancer mouse models with CSCs to elucidate the role of CSCs in resistance to targeted therapeutics in non-small cell lung cancer (NSCLC). Mouse lung organoids containing progenitor cells were cultured in complete medium containing lung niche factors, FGF-10 and HGF, and were infected with a retrovirus encoding a Kras mutation (G12D), an Egfr deletion, and the EML4-ALK fusion protein. These induced CSCs were transplanted into mice, and the established tumors were cultured in vitro to test for drug sensitivity to trametinib, erlotinib, and crizotinib in the presence or absence of niche factors. The tumors that were poorly differentiated contained EpCAM-, Cd49f-, and Sca-1-positive CSCs. These mouse models allowed the prediction of clinical responses to targeted therapeutics, i.e., the tumor cells with the Egfr deletion and those with EML4-ALK fusion proteins showed strong responses to erlotinib and crizotinib, respectively. In addition, we found that Kras mutant cancer cells were resistant to trametinib due to activation of the HGF/Met pathway since HGF is an essential niche factor for lung progenitor cell proliferation. Combination treatment with trametinib and a Met inhibitor showed a synergistic effect in Kras mutant tumors. Based on these results, we propose a treatment approach that focuses on the use of niche factors for lung progenitor cells in NSCLC. Citation Format: Akinori Mitsui, Sachiko Yokokawa, Osamu Nagano, Hideyuki Saya. Lung niche factors for progenitor cell self-renewal sustain lung cancer stem cells and contribute to drug resistance to kinase inhibitors in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2156.

Abstract 5906: EGFR and SOX2 crosstalk determines EGFR-TKI

Abstract Activating mutations in the epidermal growth factor receptor (EGFR), while initiating lung tumorigenesis, render tumors susceptible to EGFR-tyrosine kinase inhibitors (TKIs). SOX2 functions as a cell fate determination factor in lung progenitor cells. However, how SOX2 expression affects TKI treatment and tumor invasion in lung cancer is obscure. Here we report that EGFR mutations crosstalk with SOX2 to maintain cell proliferation and barrier properties in lung cancer cells, some of which generate heterogeneity by switching off SOX2 expression, thus promoting TKI resistance and invasiveness. Downregulation of SOX2 expression by shRNA against SOX2 or TGF-beta treatment induced epithelial-to-mesenchymal transition (EMT) and endowed cell resistant to TKIs. TKI treatment selected EGFR-mutated lung cancer cells harboring low SOX2 expression with the EMT signature. TKI naïve EGFR-mutated lung cancer cells harboring low SOX2 expression exhibits intrinsic TKI resistance. Conversely, enhancing endogenous SOX2 expression reverses EMT and increases sensitivity to TKIs. Immunohistochemistry analysis revealed that low SOX2 expression predicts a poor survival in patients harboring EGFR mutations. Taken together, our findings show how cancer plasticity elicited by SOX2 expression and TKI selection generates distinct oncogenic properties and TKI sensitivity, providing critical insights into tumor progression in EGFR-mutated lung cancer. Citation Format: An-Chun Lee, Chia-Cherng Yu, Yuan-Hung Wang, Yu-Ting Chou. EGFR and SOX2 crosstalk determines EGFR-TKI [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5906.

GATA6 suppression enhances lung specification from human pluripotent stem cells.

The transcription factor GATA6 has been shown to be important for lung development and branching morphogenesis in mouse models, but its role in human lung development is largely unknown. Here, we studied the role of GATA6 during lung differentiation using human pluripotent stem cells. We found that the human stem cell lines most efficient at generating NKX2.1+ lung progenitors express lower endogenous levels of GATA6 during endoderm patterning and that knockdown of GATA6 during endoderm patterning increased the generation of these cells. Complete ablation of GATA6 resulted in the generation of lung progenitors displaying increased cell proliferation with up to a 15-fold expansion compared with control cells, whereas the null cell line displayed a defect in further development into mature lung cell types. Furthermore, transgenic expression of GATA6 at the endoderm anteriorization stage skewed development toward a liver fate at the expense of lung progenitors. Our results suggest a critical dosage effect of GATA6 during human endoderm patterning and a later requirement during terminal lung differentiation. These studies offer an approach of modulating GATA6 expression to enhance the production of lung progenitors from human stem cell sources.

Abstract PR11: Investigating lung cancer cells-of-origin using three-dimensional organoid cultures

Abstract There are many distinct epithelial cell types in the adult lung that could give rise to non-small cell lung cancer. These cell types include tracheal basal stem cells, tracheal club cells, distal lung bronchioalveolar stem cells (BASCs), and distal lung alveolar type 2 cells (AT2). My laboratory is using mouse models to test directly which lung stem and progenitor cells are most fit to serve as cells-of-origin of lung adenocarcinoma and lung squamous cell carcinoma. Previously, we demonstrated that tracheal club cells and BASCs are the likely cells-of-origin for KRASG12D; Lkb1-null adenosquamous tumors. The same strategy is now being used to test which cells can give rise to adenocarcinomas using the LSL:EGFRT90M/L858R (LSL=lox-stop-lox) mouse strain, or squamous cell carcinoma using the Lkb1flox/flox; Ptenflox/flox mouse strain. Briefly, tracheas and lungs from Cre-naïve mice are enzymatically dissociated, and fluorescence activated cell sorting (FACS) is used to enrich for four distinct populations: NGFR+/Sca1+ tracheal basal cells, NGFR-/Sca1+ tracheal club cells, Sca1+ distal lung BASCs, and Sca1- distal lung AT2 cells. Each population is then incubated with either adeno-GFP control virus or adeno-Cre virus to induce EGFR T790M/L858R expression or delete both alleles of Lkb1 and Pten. Three dimensional air-liquid-interface cultures are then used to expand the populations as organoids. For EGFR organoids, both basal and club cells give rise to larger, faster-growing bronchiolar organoids after EGFR is induced. AT2 cells similarly give rise to much larger alveolar organoids after EGFR induction, and BASCs change from giving rise to both bronchiolar and alveolar organoids to nearly exclusively alveolar. For Lkb1/Pten organoids, all four populations can tolerate deletion of the two genes, but it is only the basal cell and club cell organoids that progress to a squamous morphology in vitro. While both BASC and AT2 organoids continue to grow, they appear phenotypically normal. Transplant assays to assess malignancy and RNA-seq and ChIP-seq studies to explore gene transcription and epigenetic changes are under way. These experiments will shed light on the cells of the adult lung that give rise to genotype-specific tumors, and will aid us to better classify lung cancer heterogeneity from a cell-of-origin perspective. Citation Format: Kwok-Kin Wong, Carla Kim, Christine Fillmore Brainson. Investigating lung cancer cells-of-origin using three-dimensional organoid cultures [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr PR11.

Derivation of Epithelial-Only Airway Organoids from Human Pluripotent Stem Cells.

New protocols to efficiently generate functional airway epithelial organoids from human pluripotent stem cells (PSCs) would represent a major advance towards effective disease modeling, drug screening and cell based therapies for lung disorders. This unit describes an approach using stage-specific signaling pathway manipulation to differentiate cells to proximal airway epithelium via key developmental intermediates. Cells are directed via definitive endoderm (DE) to anterior foregut, and then specified to NKX2-1+ lung epithelial progenitors. These lung progenitors are purified using cell surface marker sorting and replated in defined culture conditions to form three-dimensional, epithelial-only airway organoids. This directed differentiation approach using serum-free, defined media also includes protocols for evaluation of DE induction, intracellular FACS analysis of NKX2-1 specification efficiency and enrichment, and approaches for characterization and expansion of airway organoids. Taken together, this represents an efficient and reproducible approach to generate expandable airway organoids from human PSCs for use in numerous downstream applications. © 2018 by John Wiley & Sons, Inc.

Abstract 681: Enhanced Notch3 Signaling Contributes to Pulmonary Emphysema in a Murine Model of Marfan Syndrome

Marfan syndrome (MFS) is a heritable disorder of connective tissue, caused by mutations in fibrillin-1 gene. Pulmonary emphysema is one of the most common manifestations in MFS. However, the pathogenesis and molecular mechanism of pulmonary emphysema in MFS patients is underexplored. Notch signaling is essential for lung development. It has been shown that constitutive Notch3 activation inhibited the differentiation of distal lung progenitors into alveolar cells. Upregulation of Notch3 promoted endothelial cell death. As our objective, we investigated whether Notch3 signaling plays a role in pulmonary emphysema in MFS. By using a murine model of MFS, mgR/mgR mice, we found the pulmonary emphysematous-appearing alveolar patterns in the lung of mgR/mgR mice by Verhoeff-Van Gieson connective tissue staining and H&E staining. Lungs in mgR/mgR mice had decreased septation in terminal alveoli compared to wild type controls. Western blot analysis demonstrated that Notch3 levels were increased in the lung of mgR/mgR mice compared to wild type controls. This is associated with decreased expression of vascular endothelia growth factor (VEGF) and increased matrix metalloproteinase (MMP) -2 and MMP-9 production in the lung of mgR/mgR mice. To confirm that the increased Notch3 signaling in mgR/mgR mice were responsible to structure alternations in the lung of mgR/mgR mice, mice were treated with N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglucine t-butyl ester (DAPT), a γ -secretase inhibitor of Notch signaling. DAPT treatment was able to restore the normal lung structure in mice with MFS. This study indicates that Notch3 crosstalk with VEGF signaling pathways in the lung contribute to pulmonary emphysema in mgR/mgR mice. The results may have the potential to lead to novel strategies to prevent and treat pulmonary manifestations in patients with MFS.

39 - Close neighbors in the niche: Paracrine signals from endothelial cells promote alveolar epithelial differentiation of induced pluripotent stem cell-derived lung progenitors

39 - Close neighbors in the niche: Paracrine signals from endothelial cells promote alveolar epithelial differentiation of induced pluripotent stem cell-derived lung progenitors

β-Catenin maintains lung epithelial progenitors after lung specification.

The entire lung epithelium arises from SRY box9 (SOX9)-expressing progenitors that form the respiratory tree and differentiate into airway and alveolar cells. Despite progress in understanding their initial specification within the embryonic foregut, how these progenitors are subsequently maintained is less clear. Using inducible, progenitor-specific genetic mosaic mouse models, we showed that β-catenin (CTNNB1) maintains lung progenitors by promoting a hierarchical lung progenitor gene signature, suppressing gastrointestinal (GI) genes, and regulating NK2 homeobox1 (NKX2.1) and SRY box2 (SOX2) in a developmental stage-dependent manner. At the early, but not later, stage post-lung specification, CTNNB1 cell-autonomously maintained normal NKX2.1 expression levels and suppressed ectopic SOX2 expression. Genetic epistasis analyses revealed that CTNNB1 is required for fibroblast growth factor (Fgf)/Kirsten rat sarcoma viral oncogene homolog (Kras)-mediated promotion of the progenitors. In silico screening of Eurexpress and translating ribosome affinity purification (TRAP)-RNAseq identified a progenitor gene signature, a subset of which depends on CTNNB1. Wnt signaling also maintained NKX2.1 expression and suppressed GI genes in cultured human lung progenitors derived from embryonic stem cells.

Regeneration of the lung alveolus by an evolutionarily conserved epithelial progenitor.

Functional tissue regeneration is required for restoration of normal organ homeostasis after severe injury. While some organs, such as the intestine, harbor active stem cells throughout homeostasis and regeneration1, more quiescent organs like the lung often contain facultative progenitor cells which are recruited after injury to participate in regeneration2,3. Here we show that a Wnt-responsive alveolar epithelial progenitor (AEP) lineage within the alveolar type 2 (AT2) cell population acts as a major facultative progenitor cell in the distal lung. AEPs are a stable lineage during alveolar homeostasis but expand rapidly to regenerate a large proportion of the alveolar epithelium after acute lung injury. AEPs exhibit a distinct transcriptome, epigenome, and functional phenotype with specific responsiveness to Wnt and Fgf signaling. In distinction to other proposed lung progenitor cells, human AEPs (hAEPs) can be directly isolated via expression of the conserved cell surface marker TM4SF1, and hAEPs act as functional human alveolar epithelial progenitor cells in 3D organoids. Together, our results identify the AEP lineage as an evolutionarily conserved alveolar progenitor and a new target for human lung regeneration strategies.

Claudin-18-mediated YAP activity regulates lung stem and progenitor cell homeostasis and tumorigenesis.

Claudins, the integral tight junction (TJ) proteins that regulate paracellular permeability and cell polarity, are frequently dysregulated in cancer; however, their role in neoplastic progression is unclear. Here, we demonstrated that knockout of Cldn18, a claudin family member highly expressed in lung alveolar epithelium, leads to lung enlargement, parenchymal expansion, increased abundance and proliferation of known distal lung progenitors, the alveolar epithelial type II (AT2) cells, activation of Yes-associated protein (YAP), increased organ size, and tumorigenesis in mice. Inhibition of YAP decreased proliferation and colony-forming efficiency (CFE) of Cldn18-/- AT2 cells and prevented increased lung size, while CLDN18 overexpression decreased YAP nuclear localization, cell proliferation, CFE, and YAP transcriptional activity. CLDN18 and YAP interacted and colocalized at cell-cell contacts, while loss of CLDN18 decreased YAP interaction with Hippo kinases p-LATS1/2. Additionally, Cldn18-/- mice had increased propensity to develop lung adenocarcinomas (LuAd) with age, and human LuAd showed stage-dependent reduction of CLDN18.1. These results establish CLDN18 as a regulator of YAP activity that serves to restrict organ size, progenitor cell proliferation, and tumorigenesis, and suggest a mechanism whereby TJ disruption may promote progenitor proliferation to enhance repair following injury.

Glycogen synthase kinase 3 induces multilineage maturation of human pluripotent stem cell-derived lung progenitors in 3D culture.

Although strategies for directed differentiation of human pluripotent stem cells (hPSCs) into lung and airway have been established, terminal maturation of the cells remains a vexing problem. We show here that in collagen I 3D cultures in the absence of glycogen synthase kinase 3 (GSK3) inhibition, hPSC-derived lung progenitors (LPs) undergo multilineage maturation into proximal cells, type I alveolar epithelial cells and morphologically mature type II cells. Enhanced cell cycling, one of the signaling outputs of GSK3 inhibition, plays a role in the maturation-inhibiting effect of GSK3 inhibition. Using this model, we show NOTCH signaling induced a distal cell fate at the expense of a proximal and ciliated cell fate, whereas WNT signaling promoted a proximal club cell fate, thus implicating both signaling pathways in proximodistal specification in human lung development. These findings establish an approach to achieve multilineage maturation of lung and airway cells from hPSCs, demonstrate a pivotal role of GSK3 in the maturation of lung progenitors and provide novel insight into proximodistal specification during human lung development.

Bioengineered Lungs: A Challenge and An Opportunity

Lung biofabrication is a new tissue engineering and regenerative development aimed at providing organs for potential use in transplantation. Lung biofabrication is based on seeding cells into an acellular organ scaffold and on culturing them in an especial purpose bioreactor. The acellular lung scaffold is obtained by decellularizing a non-transplantable donor lung by means of conventional procedures based on application of physical, enzymatic and detergent agents. To avoid immune recipient's rejection of the transplanted bioengineered lung, autologous bone marrow/adipose tissue-derived mesenchymal stem cells, lung progenitor cells or induced pluripotent stem cells are used for biofabricating the bioengineered lung. The bioreactor applies circulatory perfusion and mechanical ventilation with physiological parameters to the lung during biofabrication. These physical stimuli to the organ are translated into the stem cell local microenvironment – e.g. shear stress and cyclic stretch – so that cells sense the physiological conditions in normally functioning mature lungs. After seminal proof of concept in a rodent model was published in 2010, the hypothesis that lungs can be biofabricated is accepted and intense research efforts are being devoted to the topic. The current experimental evidence obtained so far in animal tests and in ex vivo human bioengineered lungs suggests that the date of first clinical tests, although not immediate, is coming. Lung bioengineering is a disrupting concept that poses a challenge for improving our basic science knowledge and is also an opportunity for facilitating lung transplantation in future clinical translation.

Lung Injury Repair by Transplantation of Adult Lung Cells Following Preconditioning of Recipient Mice

Repair of injured lungs represents a longstanding therapeutic challenge. We recently demonstrated that human and mouse embryonic lung tissue from the canalicular stage of development are enriched with lung progenitors, and that a single cell suspension of canalicular lungs can be used for transplantation, provided that lung progenitor niches in the recipient mice are vacated by strategies similar to those used in bone marrow transplantation. Considering the ethical limitations associated with the use of fetal cells, we investigated here whether adult lungs could offer an alternative source of lung progenitors for transplantation. We show that intravenous infusion of a single cell suspension of adult mouse lungs from GFP+ donors, following conditioning of recipient mice with naphthalene and subsequent sublethal irradiation, led to marked colonization of the recipient lungs, at 6–8 weeks post‐transplant, with donor derived structures including epithelial, endothelial, and mesenchymal cells. Epithelial cells within these donor‐derived colonies expressed markers of functionally distinct lung cell types, and lung function, which is significantly compromised in mice treated with naphthalene and radiation, was found to be corrected following transplantation. Dose response analysis suggests that the frequency of patch forming cells in adult lungs was about threefold lower compared to that found in E16 fetal lungs. However, as adult lungs are much larger, the total number of patch forming cells that can be collected from this source is significantly greater. Our study provides proof of concept for lung regeneration by adult lung cells after preconditioning to vacate the pulmonary niche. stem cells translational medicine 2018;7:68–77

Long Noncoding RNA RP11-380D23.2 Drives Distal-Proximal Patterning of the Lung by Regulating PITX2 Expression.

Early lung development is a tightly orchestrated process encompassing (a) formation of definitive endoderm, (b) anteriorization of definitive endoderm, followed by (c) specification and maturation of both proximal and distal lung precursors. Several reports detailing the interaction of genes and proteins during lung development are available; however, studies reporting the role(s) of long noncoding RNAs (lncRNA) in lung morphogenesis are limited. To investigate this, we tailored a protocol for differentiation of human-induced pluripotent stem cells into distal and proximal lung progenitors to mimic in vivo lung development. The authenticity of differentiated cells was confirmed by expression of key lung markers such as FoxA2, Sox-17, Nkx2.1, Pitx2, FoxJ1, CC10, SPC, and via scanning as well as transmission electron microscopy. We employed next generation sequencing to identify lncRNAs and categorized them based on their proximity to genes essential for lung morphogenesis. In-depth bioinformatical analysis of the sequencing data enabled identification of a novel lncRNA, RP11-380D23.2, which is located upstream of PITX2 and includes a binding site for PARP1. Chromatin immunoprecipitation and other relevant studies revealed that PARP1 is a repressor for PITX2. Whole genome microarray analysis of RP11-380D23.2/PITX2 knockdown populations of progenitors demonstrated enrichment in proximal progenitors and indicated altered distal-proximal patterning. Dysregulation of WNT effectors in both knockdowns highlighted direct modulation of PITX2 by RP11-380D23.2. Most of these results were validated in four independent hiPSC lines (including a patient-specific CFTR mutant line). Taken together, these findings offer a mechanistic explanation underpinning the role of RP11-380D23.2 during lung morphogenesis via WNT signaling. Stem Cells 2018;36:218-229.

Bioengineered lungs generated from human iPSCs-derived epithelial cells on native extracellular matrix.

The development of an alternative source for donor lungs would change the paradigm of lung transplantation. Recent studies have demonstrated the potential feasibility of using decellularized lungs as scaffolds for lung tissue regeneration and subsequent implantation. However, finding a reliable cell source and the ability to scale up for recellularization of the lung scaffold still remain significant challenges. To explore the possibility of regeneration of human lung tissue from stem cells in vitro, populations of lung progenitor cells were generated from human iPSCs. To explore the feasibility of producing engineered lungs from stem cells, we repopulated decellularized human lung and rat lungs with iPSC-derived epithelial progenitor cells. The iPSCs-derived epithelial progenitor cells lined the decellularized human lung and expressed most of the epithelial markers when were cultured in a lung bioreactor system. In decellularized rat lungs, these human-derived cells attach and proliferate in a manner similar to what was observed in the decellularized human lung. Our results suggest that repopulation of lung matrix with iPSC-derived lung epithelial cells may be a viable strategy for human lung regeneration and represents an important early step toward translation of this technology.

3D culture of multipotent Sox9+ mouse embryonic lung progenitors: Isolation, Expansion and Cryopreservation

3D culture of multipotent Sox9+ mouse embryonic lung progenitors: Isolation, Expansion and Cryopreservation

Isolation and 3D expansion of multipotent Sox9+ mouse lung progenitors.

Multiple adult tissues are maintained by stem cells of restricted developmental potential which can only form a subset of lineages within the tissue. For instance, the two adult lung epithelial compartments (airways and alveoli) are separately maintained by distinct lineage-restricted stem cells. A challenge has been to obtain multipotent stem cells and/or progenitors that can generate all epithelial cell types of a given tissue. Here we show that mouse Sox9+ multipotent embryonic lung progenitors can be isolated and expanded long term in 3D culture. Cultured Sox9+ progenitors transcriptionally resemble their in vivo counterparts and generate both airway and alveolar cell types in vitro. Sox9+ progenitors that were transplanted into injured adult mouse lungs differentiated into all major airway and alveolar lineages in vivo in a region-appropriate fashion. We propose that a single expandable embryonic lung progenitor population with broader developmental competence may eventually be used as an alternative for region-restricted adult tissue stem cells in regenerative medicine.

Bioengineered Lungs: A Challenge and An Opportunity

Lung biofabrication is a new tissue engineering and regenerative development aimed at providing organs for potential use in transplantation. Lung biofabrication is based on seeding cells into an acellular organ scaffold and on culturing them in an especial purpose bioreactor. The acellular lung scaffold is obtained by decellularizing a non-transplantable donor lung by means of conventional procedures based on application of physical, enzymatic and detergent agents. To avoid immune recipient's rejection of the transplanted bioengineered lung, autologous bone marrow/adipose tissue-derived mesenchymal stem cells, lung progenitor cells or induced pluripotent stem cells are used for biofabricating the bioengineered lung. The bioreactor applies circulatory perfusion and mechanical ventilation with physiological parameters to the lung during biofabrication. These physical stimuli to the organ are translated into the stem cell local microenvironment – e.g. shear stress and cyclic stretch – so that cells sense the physiological conditions in normally functioning mature lungs. After seminal proof of concept in a rodent model was published in 2010, the hypothesis that lungs can be biofabricated is accepted and intense research efforts are being devoted to the topic. The current experimental evidence obtained so far in animal tests and in ex vivo human bioengineered lungs suggests that the date of first clinical tests, although not immediate, is coming. Lung bioengineering is a disrupting concept that poses a challenge for improving our basic science knowledge and is also an opportunity for facilitating lung transplantation in future clinical translation.

"Intersections of lung progenitor cells, lung disease and lung cancer." Carla F. Kim. Eur Respir Rev 2017; 26: 170054.

"Intersections of lung progenitor cells, lung disease and lung cancer." Carla F. Kim. Eur Respir Rev 2017; 26: 170054.

Human induced pluripotent stem cell–derived lung progenitor and alveolar epithelial cells attenuate hyperoxia-induced lung injury

Background aimsBronchopulmonary dysplasia (BPD), a chronic lung disease characterized by disrupted lung growth, is the most common complication in extreme premature infants. BPD leads to persistent pulmonary disease later in life. Alveolar epithelial type 2 cells (AEC2s), a subset of which represent distal lung progenitor cells (LPCs), promote normal lung growth and repair. AEC2 depletion may contribute to persistent lung injury in BPD. We hypothesized that induced pluripotent stem cell (iPSC)-derived AECs prevent lung damage in experimental oxygen-induced BPD. MethodsMouse AECs (mAECs), miPSCs/mouse embryonic stem sells, human umbilical cord mesenchymal stromal cells (hUCMSCs), human (h)iPSCs, hiPSC-derived LPCs and hiPSC-derived AECs were delivered intratracheally to hyperoxia-exposed newborn mice. Cells were pre-labeled with a red fluorescent dye for in vivo tracking. ResultsAirway delivery of primary mAECs and undifferentiated murine pluripotent cells prevented hyperoxia-induced impairment in lung function and alveolar growth in neonatal mice. Similar to hUCMSC therapy, undifferentiated hiPSCs also preserved lung function and alveolar growth in hyperoxia-exposed neonatal NOD/SCID mice. Long-term assessment of hiPSC administration revealed local teratoma formation and cellular infiltration in various organs. To develop a clinically relevant cell therapy, we used a highly efficient method to differentiate hiPSCs into a homogenous population of AEC2s. Airway delivery of hiPSC-derived AEC2s and hiPSC-derived LPCs, improved lung function and structure and resulted in long-term engraftment without evidence of tumor formation. ConclusionshiPSC-derived AEC2 therapy appears effective and safe in this model and warrants further exploration as a therapeutic option for BPD and other lung diseases characterized by AEC injury.