Project description:The derivation of self-renewing tissue-specific stem cells from human induced pluripotent stem cells (iPSCs) would shorten the time needed to engineer mature cell types in vitro and would have broad reaching implications for the field of regenerative medicine. Here we report the directed differentiation of human iPSCs into putative airway basal cells (“iBCs”), a population resembling the epithelial stem cell of lung airways. Using a dual fluorescent reporter system (NKX2-1GFP;TP63tdTomato) we track and purify these cells over time, as they first emerge from iPSC-derived foregut endoderm as developmentally immature NKX2-1GFP+ lung progenitors which then augment a TP63 program during subsequent proximal airway epithelial patterning. These cells clonally proliferate, initially as NKX2-1GFP+/ TP63tdTomato+ immature airway progenitors that lack expression of the adult basal cell surface marker, NGFR. However, in response to primary basal cell media, NKX2-1GFP+/ TP63tdTomato+ cells upregulate NGFR and display the molecular and functional phenotype of airway basal stem cells, including the capacity to clonally self-renew or undergo multilineage ciliated and secretory epithelial differentiation in air-liquid interface cultures. iBCs and their differentiated progeny recapitulate several fundamental physiologic features of normal primary airway epithelial cells and model perturbations that characterize acquired and genetic airway diseases. In an asthma model of mucus metaplasia, the inflammatory cytokine IL-13 induced an increase in MUC5AC+ cells similar to primary cells. CFTR-dependent chloride flux in airway epithelium generated from cystic fibrosis iBCs or their syngeneic CFTR-corrected controls exhibited a pattern consistent with the flux measured in primary diseased and normal human airway epithelium, respectively. Finally, multiciliated cells generated from an individual with primary ciliary dyskinesia recapitulated the ciliary beat and ultrastructural defects observed in the donor. Thus, we demonstrate the successful de novo generation of a tissue-resident stem cell-like population in vitro from iPSCs, an approach which should facilitate disease modeling and future regenerative therapies for a variety of diseases affecting the lung airways.Single-cell RNA-Sequencing profiling of human iPSC-derived basal cells, airway epithelium compared to primary human basal cells and airway epithelium.
Project description:Background. The human airway epithelium consists of 4 major cell types: ciliated, secretory, columnar and basal cells. During natural turnover and in response to injury, the airway basal cells function as stem / progenitor cells for the other airway cell types. The objective of this study is to better understand basal cell biology by defining the subset of expressed genes that characterize the signature of human airway epithelial basal cells. Methodology / Principal Findings. Microarrays were used to assess the transcriptome of basal cells purified from the airway epithelium of healthy nonsmokers obtained by bronchial brushings in comparison to the transcriptome of the complete differentiated airway epithelium. This analysis identified the “human airway basal cell signature” as 1,161 unique genes with >5-fold higher expression level in basal cells compared to the differentiated epithelium. The basal cell signature was suppressed when the basal cells differentiated into a ciliated airway epithelium in vitro. The human airway basal cell signature displayed extensive overlap with genes expressed in basal cells from other human tissues and murine airway basal cells. Consistent with self-modulation as well as signaling to other airway cell types, the airway basal cell signature was characterized by genes encoding extracellular matrix components, and growth factors and growth factor receptors, including genes related to EGFR and VEGFR signaling. However, while human airway basal cells share similarity with basal-like cells of other organs, the human airway basal cell signature has features not previously associated with this cell type, including a unique pattern of genes encoding extracellular matrix components, integrins, G protein-coupled receptors, neuroactive ligands and receptors, and ion channels. Conclusion / Significance. The human airway epithelial basal cells signature identified in the present study provides novel insights into the ontogeny, molecular phenotype and biology of the stem / progenitor cells of the human airway epithelium. This study was designed to distinguish the transcriptome of the airway epithelium basal cell from that of differentiated airway epithelium. A basal cell signature was derived and analyzed for functional significance. The signature was also evaluated as basal cells differentiated into ciliated epithelium in vitro.
Project description:Background. The human airway epithelium consists of 4 major cell types: ciliated, secretory, columnar and basal cells. During natural turnover and in response to injury, the airway basal cells function as stem / progenitor cells for the other airway cell types. The objective of this study is to better understand basal cell biology by defining the subset of expressed genes that characterize the signature of human airway epithelial basal cells. Methodology / Principal Findings. Microarrays were used to assess the transcriptome of basal cells purified from the airway epithelium of healthy nonsmokers obtained by bronchial brushings in comparison to the transcriptome of the complete differentiated airway epithelium. This analysis identified the “human airway basal cell signature” as 1,161 unique genes with >5-fold higher expression level in basal cells compared to the differentiated epithelium. The basal cell signature was suppressed when the basal cells differentiated into a ciliated airway epithelium in vitro. The human airway basal cell signature displayed extensive overlap with genes expressed in basal cells from other human tissues and murine airway basal cells. Consistent with self-modulation as well as signaling to other airway cell types, the airway basal cell signature was characterized by genes encoding extracellular matrix components, and growth factors and growth factor receptors, including genes related to EGFR and VEGFR signaling. However, while human airway basal cells share similarity with basal-like cells of other organs, the human airway basal cell signature has features not previously associated with this cell type, including a unique pattern of genes encoding extracellular matrix components, integrins, G protein-coupled receptors, neuroactive ligands and receptors, and ion channels. Conclusion / Significance. The human airway epithelial basal cells signature identified in the present study provides novel insights into the ontogeny, molecular phenotype and biology of the stem / progenitor cells of the human airway epithelium.
Project description:The derivation of tissue-specific stem cells from human induced pluripotent stem cells (iPSCs) would have broad reaching implications for regenerative medicine. Here, we report the directed differentiation of human iPSCs into airway basal cells ("iBCs"), a population resembling the stem cell of the airway epithelium. Using a dual fluorescent reporter system (NKX2-1GFP;TP63tdTomato), we track and purify these cells as they first emerge as developmentally immature NKX2-1GFP+ lung progenitors and subsequently augment a TP63 program during proximal airway epithelial patterning. In response to primary basal cell medium, NKX2-1GFP+/TP63tdTomato+ cells display the molecular and functional phenotype of airway basal cells, including the capacity to self-renew or undergo multi-lineage differentiation in vitro and in tracheal xenografts in vivo. iBCs and their differentiated progeny model perturbations that characterize acquired and genetic airway diseases, including the mucus metaplasia of asthma, chloride channel dysfunction of cystic fibrosis, and ciliary defects of primary ciliary dyskinesia.
Project description:Activation of the human embryonic stem cell (hESC)-signature genes has been observed in various epithelial cancers. In this study, we found that the hESC signature is selectively induced in the airway basal stem/progenitor cell population of healthy smokers (BC-S), with a pat-tern similar to that activated in all major types of human lung cancer. We further identified a subset of 6 BC-S hESC genes, whose coherent overexpression in lung AdCa was associated with reduced lung function, poorer differentiation grade, more advanced tumor stage, remarkably shorter survival and higher frequency of TP53 mutations. BC-S shared with hESC and a consid-erable subset of lung carcinomas a common TP53 inactivation molecular pattern which strongly correlated with the BC-S hESC gene expression. These data provide transcriptome-based evi-dence that smoking-induced reprogramming of airway BC towards the hESC-like phenotype might represent a common early molecular event in the development of aggressive lung carci-nomas in humans. Affymetrix arrays were used to assess gene expression data of genes realted to human embryonic stem cells in large airway epithelium obtained by fiberoptic bronchoscopy of 21 healthy non-smokers and 31 healthy smokers, basal cell culture of large airway epithelium obtained by fiberoptic bronchoscopy of 4 healthy nonsmokers and 4 healthy smokers and cells obtained from tumor tissues of 4 individuals.
Project description:Congenital diaphragmatic hernia (CDH) is characterized by incomplete closure of the diaphragm and lung hypoplasia. The pathophysiology of lung defects in CDH is poorly understood. To establish a translational model of human airway epithelium in CDH for pathogenic investigation and therapeutic testing, we developed a robust methodology of epithelial progenitor derivation from tracheal aspirates of newborns. Basal stem cells from CDH patients and preterm and term, non-CDH controls were derived and analyzed by bulk RNA-sequencing, ATAC-sequencing, and air-liquid-interface differentiation. Transcriptomic and epigenetic profiling of CDH and non-CDH basal stem cells reveals a disease-specific, proinflammatory signature independent of severity or hernia size. In addition, CDH basal stem cells exhibit defective epithelial differentiation in vitro that recapitulates epithelial phenotypes found in fetal human CDH lung samples and fetal tracheas of the nitrofen rat model of CDH. Furthermore, steroid treatment normalizes epithelial differentiation phenotypes of human CDH basal stem cells in vitro and in nitrofen rat tracheas in vivo. Our findings have identified an interplay between a proinflammatory signature and BSC differentiation as a potential therapeutic target for airway epithelial defects in CDH.
Project description:Congenital diaphragmatic hernia (CDH) is characterized by incomplete closure of the diaphragm and lung hypoplasia. The pathophysiology of lung defects in CDH is poorly understood. To establish a translational model of human airway epithelium in CDH for pathogenic investigation and therapeutic testing, we developed a robust methodology of epithelial progenitor derivation from tracheal aspirates of newborns. Basal stem cells from CDH patients and preterm and term, non-CDH controls were derived and analyzed by bulk RNA-sequencing, ATAC-sequencing, and air-liquid-interface differentiation. Transcriptomic and epigenetic profiling of CDH and non-CDH basal stem cells reveals a disease-specific, proinflammatory signature independent of severity or hernia size. In addition, CDH basal stem cells exhibit defective epithelial differentiation in vitro that recapitulates epithelial phenotypes found in fetal human CDH lung samples and fetal tracheas of the nitrofen rat model of CDH. Furthermore, steroid treatment normalizes epithelial differentiation phenotypes of human CDH basal stem cells in vitro and in nitrofen rat tracheas in vivo. Our findings have identified an interplay between a proinflammatory signature and BSC differentiation as a potential therapeutic target for airway epithelial defects in CDH.