Lung Progenitor Research Articles

Engineered hydrogel biomaterials facilitate lung progenitor cell differentiation from induced pluripotent stem cells.

Lung progenitor (LP) cells identified by the expression of transcription factor NK2 homeobox 1 (NKX2.1) are essential for development of all lung epithelial cell types and hold tremendous potential for pulmonary research and translational regenerative medicine applications. Here we present engineered hydrogels as a promising alternative to the naturally derived materials that are often used to differentiate human induced pluripotent stem cells (iPSCs) into LP cells. Poly(ethylene glycol) norbornene (PEGNB) hydrogels with defined composition were used to systematically investigate the role of microenvironmental stiffness, cell origin, and splitting during the differentiation process. Results demonstrated each factor impacted LP differentiation efficiency and that the soft hydrogels replicating healthy lung stiffness (Elastic modulus (E), E = 4.00 ± 0.25 kPa) produced the highest proportion of LP cells based on flow cytometric analysis results (54%) relative to the stiff hydrogels (48%) and Matrigel controls (32%) at the end of the non-split differentiation protocol. Collectively these results showed that engineered hydrogels provide a well-defined microenvironment for iPSC-to-LP differentiation and perform as effectively as the current gold standard Matrigel-coated tissue culture plastic. Adopting engineered biomaterials in cell culture protocols may enable greater control over differentiation parameters and has the potential to enhance the clinical translation of iPSC-derived LP cells.

Human Induced Lung Organoids: A Promising Tool for Cystic Fibrosis Drug Screening.

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. Currently, CFTR modulators are the most effective treatment for CF; however, they may not be suitable for all patients. A representative and convenient in vitro model is needed to screen therapeutic agents under development. This study, on the most common mutation, F508del, investigates the efficacy of human induced pluripotent stem cell-derived lung organoids (hiLOs) from NKX2.1+ lung progenitors and airway basal cells (hiBCs) as a 3D model for CFTR modulator response assessment by a forskolin-induced swelling assay. Weak swelling was observed for hiLOs from NKX2.1+ lung progenitors and hiBCs in response to modulators VX-770/VX-809 and VX-770/VX-661, whereas the VX-770/VX-661/VX-445 combination resulted in the highest swelling response, indicating superior CFTR function restoration. The ROC analysis of the FIS assay results revealed an optimal cutoff of 1.21, with 65.9% sensitivity and 71.8% specificity, and the predictive accuracy of the model was 76.4%. In addition, this study compared the response of hiLOs with the clinical response of patients to therapy and showed similar drug response dynamics. Thus, hiLOs can effectively model the CF pathology and predict patients' specific response to modulators.

Advancing the Battle against Cystic Fibrosis: Stem Cell and Gene Therapy Insights.

Cystic fibrosis (CF) is a hereditary disorder characterized by mutations in the CFTR gene, leading to impaired chloride ion transport and subsequent thickening of mucus in various organs, particularly the lungs. Despite significant progress in CF management, current treatments focus mainly on symptom relief and do not address the underlying genetic defects. Stem cell and gene therapies present promising avenues for tackling CF at its root cause. Stem cells, including embryonic, induced pluripotent, mesenchymal, hematopoietic, and lung progenitor cells, offer regenerative potential by differentiating into specialized cells and modulating immune responses. Similarly, gene therapy aims to correct CFTR gene mutations by delivering functional copies of the gene into affected cells. Various approaches, such as viral and nonviral vectors, gene editing with CRISPR-Cas9, small interfering RNA (siRNA) therapy, and mRNA therapy, are being explored to achieve gene correction. Despite their potential, challenges such as safety concerns, ethical considerations, delivery system optimization, and long-term efficacy remain. This review provides a comprehensive overview of the current understanding of CF pathophysiology, the rationale for exploring stem cell and gene therapies, the types of therapies available, their mechanisms of action, and the challenges and future directions in the field. By addressing these challenges, stem cell and gene therapies hold promise for transforming CF management and improving the quality of life of affected individuals.

Morphogenesis and regeneration share a conserved core transition cell state program that controls lung epithelial cell fate.

Transitional cell states are at the crossroads of crucial developmental and regenerative events, yet little is known about how these states emerge and influence outcomes. The alveolar and airway epithelia arise from distal lung multipotent progenitors, which undergo cell fate transitions to form these distinct compartments. The identification and impact of cell states in the developing lung are poorly understood. Here, we identified a population of Icam1/Nkx2-1 epithelial progenitors harboring a transitional state program remarkably conserved in humans and mice during lung morphogenesis and regeneration. Lineage-tracing and functional analyses reveal their role as progenitors to both airways and alveolar cells and the requirement of this transitional program to make distal lung progenitors competent to undergo airway cell fate specification. The identification of a common progenitor cell state in vastly distinct processes suggests a unified program reiteratively regulating outcomes in development and regeneration.

The Homeobox Transcription Factor Cux1 Coordinates Postnatal Epithelial Developmental Timing but Is Dispensable for Lung Organogenesis and Regeneration.

Lung epithelial progenitors use a complex network of known and predicted transcriptional regulators to influence early lung development. Here, we evaluate the function of one predicted regulator, Cux1, that we identified from transcriptional regulatory analysis of the SOX9+ distal lung progenitor network. We generated a new Cux1-floxed mouse model and created an epithelial-specific knockout of Cux1 using Shh-Cre (Cux1ShhCre-LOF). Postnatal Cux1ShhCre-LOF animals recapitulated key skin phenotypic features found in prior constitutive Cux1 knockout animals, confirming functionality of our new floxed model. Postnatal Cux1ShhCre-LOF mice displayed subtle alveolar simplification and a transient delay in alveologenesis and alveolar type 1 cell development without persistent lung phenotypes. Cux1ShhCre-LOF mice developed failure to thrive in their second and third weeks of life due to delayed ileal maturation, which similarly resolves by postnatal day 35. Finally, we challenged Cux1ShhCre-LOF with influenza-mediated lung injury to demonstrate that Cux1ShhCre-LOF mice undergo productive alveolar regeneration that is indistinguishable from WT animals. Together, these findings indicate that epithelial-specific loss of Cux1 leads to transient developmental delays in the skin, lung, and intestine without defects in definitive organogenesis. We conclude that Cux1 function is required for temporal optimization of developmental maturation in multiple organs with implications for susceptibility windows in developmental disease pathogenesis.

Physiological Modeling of the Vascularized Human Lung Organoid.

Studies using human lung organoids (hLO) have focused on differentiation of lung epithelial subtypes into distal alveolar unit. A major question has been whether introducing endothelial cells (EC) and resultant vascularization alter development of hLO. We describe herein a method for vessel infiltration of hLO in which we determined differences of these hLOs with standard avascular hLOs. hLO are generated by combining hiPSC-derived lung progenitor cells (LP) with EC at different LP:EC ratios. This results in vascularization of hLO and enables comparisons with hLO generated without EC. We observe red blood-filled vessels in hLOs generated post-implantation into the kidney capsule of NOD/SCID mice. Both human and mouse EC conjoin in the capsule to form chimeric vessels in hLOs. Vessel-infiltrating hLOs show robust generation of alveolar type II epithelial cells (ATII) and alveolar type I cells (ATI), although there was no difference in the observed 1:1 ATII/ATI cell ratio. Electron microscopy revealed better-developed surfactant production apparatus in ATII of vascularized hLOs compared to avascular hLOs. We observed prominent primitive airway sacs with alveolar epithelial cells lining lumen in vascularized vs. avascular hLOs. The vessel-infiltrating hLOs also mounted a robust inflammatory response characterized by mouse PMN influx after challenging host mice with lipopolysaccharide. Thus, interaction of EC with LP generated vascularized hLOs and drive ATII and ATI differentiation and hLOs also mount a robust inflammatory response upon LPS challenge of hLO-transplanted recipient mice. Our results show usefulness of generating hLOs in studying human lung development and mechanisms underlying inflammatory lung injury.

Targeting of the IL-5 pathway in severe asthma reduces mast cell progenitors

BackgroundTherapies targeting interleukin-5 (IL-5) or its receptor (IL-5Rα) are currently used to treat patients with severe eosinophilic asthma. ObjectiveTo investigate the impact of anti-IL-5 and anti-IL-5Rα biological therapies on mast cells (MCs) and their progenitors. MethodsSurface IL-5Rα expression was investigated on MCs and their progenitors in mouse lungs and bone marrow, and in human lungs and blood. Isolated human MC progenitors cultured in the presence or absence of IL-5 were analyzed in vitro. Circulating MC progenitors were quantified in patients with severe asthma, before and after anti-IL-5 (mepolizumab) or anti-IL-5Rα (benralizumab) therapy. Gene expression analysis of MC progenitors was performed before and after anti-IL-5Rα therapy. ResultsApproximately 50% of the human primary lung MCs, and 30% of the human MC progenitors from individuals with allergic asthma expressed IL-5Rα. In patients with mild-to-moderate allergic asthma and mice with acute allergic airway inflammation, the fraction of IL-5Rα + MC progenitors was elevated. Additionally, IL-5 promoted the proliferation and/or survival of isolated human MC progenitors. Further, patients with severe asthma from two independent cohorts demonstrated a reduction of blood MC progenitors after anti-IL-5 or anti-IL-5Rα treatment. This was associated with improved asthma control, as well as a decline in both blood eosinophils and Th2 cells. Finally, the blood MC progenitors remaining after anti-IL-5Rα (benralizumab) treatment exhibited a downregulated expression of genes involved in growth and proliferation. ConclusionThis study introduces the possibility that the clinical effects of targeting IL-5/IL-5Rα in severe asthma also may involve reduction of MC populations.

Autologous transplantation of P63+ lung progenitor cells in patients with bronchiectasis: A randomized, single-blind, controlled trial

Non-cystic fibrosis bronchiectasis is a progressive respiratory disease with limited treatment options, prompting the exploration of regenerative therapies. This study investigates the safety and efficacy of autologous P63+ progenitor cell transplantation in a randomized, single-blind, controlled, phase 1/2 trial. Thirty-seven patients receive bronchoscopic airway clearance (B-ACT) (n= 19) or B-ACT plus P63+ progenitor cells (n= 18). Results show that compared to the control group, the change in DLCO levels from baseline to 24weeks post therapy is significantly higher in the cell treatment group (p value= 0.039). Furthermore, the patients in the cell treatment group demonstrate significantly reduced lung damaged area, improved SGRQ score, and ameliorated BSI and FACED scores within 4-12weeks post therapy. Transcriptomic analysis reveals that progenitor cells with higher expression of P63 gene have better therapeutic efficacy. These findings suggest that P63+ progenitor cells may offer a promising therapeutic approach for bronchiectasis. This study was registered at ClinicalTrials.gov(NCT03655808).

Autologous transplantation of lung progenitor cells comes into reality for bronchiectasis

Stem and progenitor cell-based regenerative therapies have the potential to cure chronic respiratory diseases. Yan etal.1 reported a clinical trial of autologous P63+ progenitor cell transplantation in bronchiectasis patients, highlighting autologous transplantation of P63+ progenitor cells as a novel candidate therapeutic option to improve pulmonary gas exchange function and quality of life.

PCLAF-DREAM drives alveolar cell plasticity for lung regeneration

Cell plasticity, changes in cell fate, is crucial for tissue regeneration. In the lung, failure of regeneration leads to diseases, including fibrosis. However, the mechanisms governing alveolar cell plasticity during lung repair remain elusive. We previously showed that PCLAF remodels the DREAM complex, shifting the balance from cell quiescence towards cell proliferation. Here, we find that PCLAF expression is specific to proliferating lung progenitor cells, along with the DREAM target genes transactivated by lung injury. Genetic ablation of Pclaf impairs AT1 cell repopulation from AT2 cells, leading to lung fibrosis. Mechanistically, the PCLAF-DREAM complex transactivates CLIC4, triggering TGF-β signaling activation, which promotes AT1 cell generation from AT2 cells. Furthermore, phenelzine that mimics the PCLAF-DREAM transcriptional signature increases AT2 cell plasticity, preventing lung fibrosis in organoids and mice. Our study reveals the unexpected role of the PCLAF-DREAM axis in promoting alveolar cell plasticity, beyond cell proliferation control, proposing a potential therapeutic avenue for lung fibrosis prevention.

Influence of mesenchymal and biophysical components on distal lung organoid differentiation

BackgroundChronic lung disease of prematurity, called bronchopulmonary dysplasia (BPD), lacks effective therapies, stressing the need for preclinical testing systems that reflect human pathology for identifying causal pathways and testing novel compounds. Alveolar organoids derived from human pluripotent stem cells (hPSC) are promising test platforms for studying distal airway diseases like BPD, but current protocols do not accurately replicate the distal niche environment of the native lung. Herein, we investigated the contributions of cellular constituents of the alveolus and fetal respiratory movements on hPSC-derived alveolar organoid formation.MethodsHuman PSCs were differentiated in 2D culture into lung progenitor cells (LPC) which were then further differentiated into alveolar organoids before and after removal of co-developing mesodermal cells. LPCs were also differentiated in Transwell® co-cultures with and without human fetal lung fibroblast. Forming organoids were subjected to phasic mechanical strain using a Flexcell® system. Differentiation within organoids and Transwell® cultures was assessed by flow cytometry, immunofluorescence, and qPCR for lung epithelial and alveolar markers of differentiation including GATA binding protein 6 (GATA 6), E-cadherin (CDH1), NK2 Homeobox 1 (NKX2-1), HT2-280, surfactant proteins B (SFTPB) and C (SFTPC).ResultsWe observed that co-developing mesenchymal progenitors promote alveolar epithelial type 2 cell (AEC2) differentiation within hPSC-derived lung organoids. This mesenchymal effect on AEC2 differentiation was corroborated by co-culturing hPSC-NKX2-1+ lung progenitors with human embryonic lung fibroblasts. The stimulatory effect did not require direct contact between fibroblasts and NKX2-1+ lung progenitors. Additionally, we demonstrate that episodic mechanical deformation of hPSC-derived lung organoids, mimicking in situ fetal respiratory movements, increased AEC2 differentiation without affecting proximal epithelial differentiation.ConclusionOur data suggest that biophysical and mesenchymal components promote AEC2 differentiation within hPSC-derived distal organoids in vitro.

Stem cells, cell therapies, and bioengineering in lung biology and diseases 2023.

Repair and regeneration of a diseased lung using stem cells or bioengineered tissues is an exciting therapeutic approach for a variety of lung diseases and critical illnesses. Over the past decade, increasing evidence from preclinical models suggests that mesenchymal stromal cells, which are not normally resident in the lung, can be used to modulate immune responses after injury, but there have been challenges in translating these promising findings to the clinic. In parallel, there has been a surge in bioengineering studies investigating the use of artificial and acellular lung matrices as scaffolds for three-dimensional lung or airway regeneration, with some recent attempts of transplantation in large animal models. The combination of these studies with those involving stem cells, induced pluripotent stem cell derivatives, and/or cell therapies is a promising and rapidly developing research area. These studies have been further paralleled by significant increases in our understanding of the molecular and cellular events by which endogenous lung stem and/or progenitor cells arise during lung development and participate in normal and pathological remodeling after lung injury. For the 2023 Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases Conference, scientific symposia were chosen to reflect the most cutting-edge advances in these fields. Sessions focused on the integration of "omics" technologies with function, the influence of immune cells on regeneration, and the role of the extracellular matrix in regeneration. The necessity for basic science studies to enhance fundamental understanding of lung regeneration and to design innovative translational studies was reinforced throughout the conference.

Lung cell transplantation for pulmonary fibrosis.

Idiopathic pulmonary fibrosis is a major cause of death with few treatment options. Here, we demonstrate the therapeutic efficacy for lung fibrosis of adult lung cell transplantation using a single-cell suspension of the entire lung in two distinct mouse systems: bleomycin treatment and mice lacking telomeric repeat-binding factor 1 expression in alveolar type 2 (AT2) cells (SPC-Cre TRF1fl/fl), spontaneously developing fibrosis. In both models, the progression of fibrosis was associated with reduced levels of host lung progenitors, enabling engraftment of donor progenitors without any additional conditioning, in contrast to our previous studies. Two months after transplantation, engrafted progenitors expanded to form numerous donor-derived patches comprising AT1 and AT2 alveolar cells, as well as donor-derived mesenchymal and endothelial cells. This lung chimerism was associated with attenuation of fibrosis, as demonstrated histologically, biochemically, by computed tomography imaging, and by lung function measurements. Our study provides a strong rationale for the treatment of lung fibrosis using lung cell transplantation.

Differentiation of CD166-positive hPSC-derived lung progenitors into airway epithelial cells.

The generation of lung epithelial cells through the directed differentiation of human pluripotent stem cells (hPSCs) in vitro provides a platform to model both embryonic lung development and adult airway disease. Here, we describe a robust differentiation protocol that closely recapitulates human embryonic lung development. Differentiating cells progress through obligate intermediate stages, beginning with definitive endoderm formation and then patterning into anterior foregut endoderm that yields lung progenitors (LPs) with extended culture. These LPs can be purified using the cell surface marker CD166 (also known as ALCAM), and further matured into proximal airway epithelial cells including basal cells, secretory cells and multiciliated cells using either an organoid platform or culture at the air-liquid interface (ALI). We additionally demonstrate that these hPSC-derived airway epithelial cells can be used to model Influenza A infection. Collectively, our results underscore the utility of CD166 expression for the efficient enrichment of LPs from heterogenous differentiation cultures and the ability of these isolated cells to mature into more specialized, physiologically relevant proximal lung cell types.

Airway basal cells from human-induced pluripotent stem cells: a new frontier in cystic fibrosis research.

Human-induced airway basal cells (hiBCs) derived from human-induced pluripotent stem cells (hiPSCs) offer a promising cell model for studying lung diseases, regenerative medicine, and developing new gene therapy methods. We analyzed existing differentiation protocols and proposed our own protocol for obtaining hiBCs, which involves step-by-step differentiation of hiPSCs into definitive endoderm, anterior foregut endoderm, NKX2.1+ lung progenitors, and cultivation on basal cell medium with subsequent cell sorting using the surface marker CD271 (NGFR). We derived hiBCs from two healthy cell lines and three cell lines with cystic fibrosis (CF). The obtained hiBCs, expressing basal cell markers (NGFR, KRT5, and TP63), could differentiate into lung organoids (LOs). We demonstrated that LOs derived from hiBCs can assess cystic fibrosis transmembrane conductance regulator (CFTR) channel function using the forskolin-induced swelling (FIS) assay. We also carried out non-viral (electroporation) and viral (recombinant adeno-associated virus (rAAV)) serotypes 6 and 9 and recombinant adenovirus (rAdV) serotype 5 transgene delivery to hiBCs and showed that rAAV serotype 6 is most effective against hiBCs, potentially applicable for gene therapy research.

Mapping Lung Hematopoietic Progenitors: Developmental Kinetics and Response to Influenza A Infection.

The bone marrow is a specialized niche responsible for the maintenance of hematopoietic stem and progenitor cells during homeostasis and inflammation. Recent studies, however, have extended this essential role to the extramedullary and extravascular lung microenvironment. Here, we provide further evidence for a reservoir of hematopoietic stem and progenitor cells within the lung from Embryonic Day 18.5 until adulthood. These lung progenitors display distinct microenvironment-specific developmental kinetics compared with their bone marrow counterparts, exemplified by a rapid shift from a common myeloid to a megakaryocyte-erythrocyte progenitor-dominated niche with increasing age. In adult mice, influenza A viral infection results in a transient reduction in multipotent progenitors within the lungs, with a parallel increase in downstream granulocyte-monocyte progenitors and dendritic cell populations associated with acute viral infections. Our findings suggest that lung hematopoietic progenitors play a role in reestablishing immunological homeostasis in the respiratory mucosa, which may have significant clinical implications for maintaining pulmonary health after inflammatory perturbation.

In vitro platform to model the function of ionocytes in the human airway epithelium

BackgroundPulmonary ionocytes have been identified in the airway epithelium as a small population of ion transporting cells expressing high levels of CFTR (cystic fibrosis transmembrane conductance regulator), the gene mutated in cystic fibrosis. By providing an infinite source of airway epithelial cells (AECs), the use of human induced pluripotent stem cells (hiPSCs) could overcome some challenges of studying ionocytes. However, the production of AEC epithelia containing ionocytes from hiPSCs has proven difficult. Here, we present a platform to produce hiPSC-derived AECs (hiPSC-AECs) including ionocytes and investigate their role in the airway epithelium.MethodshiPSCs were differentiated into lung progenitors, which were expanded as 3D organoids and matured by air-liquid interface culture as polarised hiPSC-AEC epithelia. Using CRISPR/Cas9 technology, we generated a hiPSCs knockout (KO) for FOXI1, a transcription factor that is essential for ionocyte specification. Differences between FOXI1 KO hiPSC-AECs and their wild-type (WT) isogenic controls were investigated by assessing gene and protein expression, epithelial composition, cilia coverage and motility, pH and transepithelial barrier properties.ResultsMature hiPSC-AEC epithelia contained basal cells, secretory cells, ciliated cells with motile cilia, pulmonary neuroendocrine cells (PNECs) and ionocytes. There was no difference between FOXI1 WT and KO hiPSCs in terms of their capacity to differentiate into airway progenitors. However, FOXI1 KO led to mature hiPSC-AEC epithelia without ionocytes with reduced capacity to produce ciliated cells.ConclusionOur results suggest that ionocytes could have role beyond transepithelial ion transport by regulating epithelial properties and homeostasis in the airway epithelium.

Abstract 4238: ModelingRET-rearranged non-small cell lung cancer (NSCLC): Generation of lung cell progenitors from patient-derived induced pluripotent stem cells (iPSCs)

Abstract Rearranged during Transfection (RET) oncogenic rearrangements can occur in 1-2% of lung adenocarcinomas. While RET-driven NSCLC models have been developed using various approaches, no model based on patient-derived induced pluripotent stem cells (iPSCs) has been described yet. Patient-derived iPSCs hold great promise for disease modeling. However, generating iPSCs with specific oncogenic drivers, like RET rearrangements, presents challenges due to reprogramming efficiency and genotypic variability within tumors. To address this issue, we aimed to generate lung progenitor cells (LPCs) from patient-derived iPSCs carrying the somatic mutation RETC634Y which is commonly associated with hereditary medullary thyroid carcinoma. Additionally, we have established a RETC634Y knock-in iPSC model to validate the effect of this oncogenic mutation during LPC differentiation. We successfully generated LPCs from RETC634Y iPSCs using a 16-days protocol and showed an overexpression of cancer-associated markers as compared to control iPSCs. Transcriptomic analysis revealed a distinct signature of NSCLC tumor repression, suggesting a lung multilineage lung dedifferentiation, along with an upregulated signature associated with RETC634Ymutation potentially linked to poor NSCLC prognosis. These findings were validated using the RETC634Y knock-in iPSC model, highlighting key cancerous targets such as PROM2 and C1QTNF6, known to be associated with poor prognostic outcomes. Furthermore, the LPCs derived from RETC634Y iPSCs exhibited a positive response to the RET inhibitor Pralsetinib, evidenced by the downregulation of the cancer markers. This study provides a novel off-the-shelf iPSC model of RET-driven NSCLC, paving the way for exploring the molecular mechanisms involved in RET-driven NSCLC to study disease progression and to uncover potential therapeutic targets. Citation Format: Paul Marcoux, Jinwook Hwang, Christophe Desterke, Jusuf Imeri, Annelise Bennaceur Griscelli, Ali Turhan. ModelingRET-rearranged non-small cell lung cancer (NSCLC): Generation of lung cell progenitors from patient-derived induced pluripotent stem cells (iPSCs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4238.

Lung Progenitor and Stem Cell Transplantation as a Potential Regenerative Therapy for Lung Diseases.

Chronic lung diseases are debilitating illnesses ranking among the top causes of death globally. Currently, clinically available therapeutic options capable of curing chronic lung diseases are limited to lung transplantation, which is hindered by donor organ shortage. This highlights the urgent need for alternative strategies to repair damaged lung tissues. Stem cell transplantation has emerged as a promising avenue for regenerative treatment of the lung, which involves delivery of healthy lung epithelial progenitor cells that subsequently engraft in the injured tissue and further differentiate to reconstitute the functional respiratory epithelium. These transplanted progenitor cells possess the remarkable ability to self-renew, thereby offering the potential for sustained long-term treatment effects. Notably, the transplantation of basal cells, the airway stem cells, holds the promise for rehabilitating airway injuries resulting from environmental factors or genetic conditions such as cystic fibrosis. Similarly, for diseases affecting the alveoli, alveolar type II cells have garnered interest as a viable alveolar stem cell source for restoring the lung parenchyma from genetic or environmentally induced dysfunctions. Expanding upon these advancements, the use of induced pluripotent stem cells to derive lung progenitor cells for transplantation offers advantages such as scalability and patient specificity. In this review, we comprehensively explore the progress made in lung stem cell transplantation, providing insights into the current state of the field and its future prospects.

Autologous transplantation of P63+ lung progenitor cells for chronic obstructive pulmonary disease therapy.

Adult lung resident stem/progenitor cells, including P63+ progenitor cells, have demonstrated the capacity for regeneration of lung epithelium in preclinical models. Here, we report a clinical trial of intrapulmonary P63+ progenitor cell transplantation in 28 participants with stage II to IV chronic obstructive pulmonary disease (COPD). Autologous P63+ progenitor cells were isolated from the airway basal layer of participants in the intervention group via bronchoscopic brushing, cultured for 3 to 5 weeks, and then transplanted back into the lungs via bronchoscopy at 0.7 × 106 to 5.2 × 106 cells per kilogram of body weight. Twenty patients were evaluable at the end of the study (intervention group, n = 17; control group, n = 3). No grade 3 to 5 adverse events (AEs) or serious AEs occurred. Although bronchoscopy-associated AEs were recorded in participants in the intervention group, other AEs were not substantial different between groups. Twenty-four weeks after transplantation, participants in the intervention group displayed improvement in gas transfer capacity [diffusing capacity of the lung for carbon monoxide (DLCO) change from baseline: +18.2%], whereas the control group experienced a decrease (DLCO change from baseline: -17.4%; P = 0.008). Furthermore, participants in the intervention group showed >30-meter increase in walking distance within 6 minutes. Transcriptomic analysis of progenitor cells isolated from responding and nonresponding individuals in the intervention group showed that higher expression of P63 was associated with treatment efficacy. In conclusion, transplantation of cultured P63+ lung progenitor cells was safe and might represent a potential therapeutic strategy for COPD.