Characterization of an Immortalized Human Small Airway Basal Stem/Progenitor Cell Line with Airway Region-specific Differentiation Capacity [RNA-Seq]
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ABSTRACT: The pathology of chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and the majority of lung cancers involve the small airway epithelium (SAE), the single continuous layer of cells lining the airways ≥6th generations. The basal cells (BC) are the stem/progenitor cells of the SAE, responsible for the differentiation into intermediate cells and ciliated, club and mucous differentiated cells. To facilitate the study of the biology of the human SAE in health and disease, we immortalized and characterized a normal human SAE basal cell line. The immortalized hSABC-NS1.1 cell line has diverse differentiation capacities and retains SAE features, which will be useful for understanding the biology of SAE, the pathogenesis of SAE-related diseases, and testing new pharmacologic agents.
Project description:The pathology of chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and the majority of lung cancers involve the small airway epithelium (SAE), the single continuous layer of cells lining the airways ?6th generations. The basal cells (BC) are the stem/progenitor cells of the SAE, responsible for the differentiation into intermediate cells and ciliated, club and mucous differentiated cells. To facilitate the study of the biology of the human SAE in health and disease, we immortalized and characterized a normal human SAE basal cell line. The immortalized hSABC-NS1.1 cell line has diverse differentiation capacities and retains SAE features, which will be useful for understanding the biology of SAE, the pathogenesis of SAE-related diseases, and testing new pharmacologic agents.
Project description:The small airway epithelium (SAE) the pseudostratified epithelium that covers the majority of the human airway surface from the 6th generation to the alveoli, is the major site of lung disease caused by smoking, and the cell population that exhibits the earliest manifestations of smoking-induced disease. The focus of this study is to use RNA-Seq (massive parallel sequencing technology) to sequence all polyA+ mRNAs expressed by the SAE of healthy nonsmokers to gain new insights into the biology of the SAE, and how these cells respond to cigarette smoke. Taking advantage of RNA-Seq providing quantitative mRNA levels, that data demonstrates that while the SAE shares its transcriptome with many cell types, it has unique characteristics that are enriched in this cell population, with the mostly highly expressed genes (SCGB1A1) characteristics of Clara cells, an airway epithelial cell unique to the human small airways. Among other genes expressed by the SAE are those characteristic of ciliated and mucin-producing cells, basal cells and neuroendocrine cells. The RNA-Seq data includes identification of the highly expressed SAE transcription factors, transmembrane receptors, signaling ligands and growth factors. RNA-Seq permitted quantification of expression of highly homologous gene families, the absolute smoking-induced changes in SAE gene expression, including genes expressed at low levels, and assessment of the effect of smoking on SAE gene splicing. Together, these observations can serve as the baseline for assessment of the dysregulation of SAE gene expression in human airway disease. The small airway epithelium (SAE) is the major site of lung disease caused by smoking, and the cell population that exhibits the earliest manifestations of smoking-induced disease. This study used RNA-Seq to sequence all polyA+ mRNAs expressed by the SAE of 5 healthy nonsmokers to gain new insights into the biology of the SAE, and evaluate how these cells respond to cigarette smoke using 6 healthy smoker samples (SRA029282.1). Taking advantage of RNA-Seq providing quantitative mRNA levels, that data demonstrates that while the SAE shares its transcriptome with many cell types, it has unique characteristics that are enriched in this cell population. Coverage of RNA-Seq expression was also compared to the HG-U133 Plus 2.0 microarray expression of 27 previously published healthy nonsmoker samples presented here.
Project description:The small airway epithelium (SAE) the pseudostratified epithelium that covers the majority of the human airway surface from the 6th generation to the alveoli, is the major site of lung disease caused by smoking, and the cell population that exhibits the earliest manifestations of smoking-induced disease. The focus of this study is to use RNA-Seq (massive parallel sequencing technology) to sequence all polyA+ mRNAs expressed by the SAE of healthy nonsmokers to gain new insights into the biology of the SAE, and how these cells respond to cigarette smoke. Taking advantage of RNA-Seq providing quantitative mRNA levels, that data demonstrates that while the SAE shares its transcriptome with many cell types, it has unique characteristics that are enriched in this cell population, with the mostly highly expressed genes (SCGB1A1) characteristics of Clara cells, an airway epithelial cell unique to the human small airways. Among other genes expressed by the SAE are those characteristic of ciliated and mucin-producing cells, basal cells and neuroendocrine cells. The RNA-Seq data includes identification of the highly expressed SAE transcription factors, transmembrane receptors, signaling ligands and growth factors. RNA-Seq permitted quantification of expression of highly homologous gene families, the absolute smoking-induced changes in SAE gene expression, including genes expressed at low levels, and assessment of the effect of smoking on SAE gene splicing. Together, these observations can serve as the baseline for assessment of the dysregulation of SAE gene expression in human airway disease.
Project description:The proximal-distal patterning program determines unique structural and functional properties of proximal and distal airways in the adult lung. Based on the knowledge that remod-eling of distal airways is the major pathologic feature of chronic obstructive pulmonary disease (COPD), and that small airway epithelium (SAE), which covers distal airways, is the primary site of the initial smoking-induced changes relevant to COPD pathogenesis, we hypothesized that in COPD smokers, the SAE transcriptome loses its region-specific biologic identity and takes on the transcriptional pattern of the proximal airways. By analyzing human airway epithelium col-lected by bronchoscopic brushings from proximal and distal airways of healthy smokers, proxi-mal and distal airway epithelial transcriptome signatures were identified. Dramatic smoking-dependent suppression of distal signature paralleled by acquisition of the proximal airway epithe-lial phenotype was found in the SAE of COPD smokers. Distal-proximal re-patterning observed in the SAE of smokers in vivo was reproduced in vitro by stimulating SAE basal cells (BC), the stem/progenitor cells of the SAE, with EGF, a growth factor up-regulated in airway epithelium by smoking. Together, this study identifies distal-proximal SAE re-patterning as a characteristic feature of small airway disordering in COPD smokers potentially driven by EGF/EGFR-mediated reprogramming of SAE BC stem/progenitor cells.
Project description:To identify key genes that define surface airway epithelial (SAE) basal cells, we FACS isolated basal, ciliated, and club cell populations as previously reported (Zhao et al., 2014; PMID: 25043474) and performed microarray analysis on isolated mRNA. For fractionating SAE into basal, club, and ciliated populations, cells were stained with EpCAM-PECy7 (eBiosciences), GSIβ4-FITC (Sigma), SSEA1-Alexa Fluor® 647 (BioLegend), and CD24-PE (BD Pharmingen) for 30 minutes on ice as previously described (Zhao et al., 2014), prior to FACS. Basal cells were considered EpCAM+ and GSIβ4+. Secretory cells were considered EpCAM+ and SSEA1+. Ciliated cells were considered EpCAM+, GSIβ4- and CD24+. Primary SAE cells were harvested from C57BL/6 mice and sorted into basal, ciliated, and club cell populations for the purpose of identifying enrichment of transcripts specific to each cell type population.
Project description:The first changes associated with smoking are in the small airway epithelium (SAE). Given that smoking alters SAE gene expression, but only a fraction of smokers develop chronic obstructive pulmonary disease (COPD), we hypothesized that assessment of SAE genome-wide gene expression would permit biologic phenotyping of the smoking response, and that a subset of healthy smokers would have a “COPD-like” SAE transcriptome. SAE (10th-12th generation) was obtained via bronchoscopy of healthy nonsmokers, healthy smokers and COPD smokers and microarray analysis was used to identify differentially expressed genes. Individual responsiveness to smoking was quantified with an index representing the % of smoking-responsive genes abnormally expressed (ISAE), with healthy smokers grouped into “high” and “low” responders based on the proportion of smoking-responsive genes up- or down-regulated in each smoker. Smokers demonstrated significant variability in SAE transcriptome with ISAE ranging from 2.9 to 51.5%. While the SAE transcriptome of “low” responder healthy smokers differed from both “high” responders and smokers with COPD, the transcriptome of the “high” responder healthy smokers was indistinguishable from COPD smokers. The SAE transcriptome can be used to classify clinically healthy smokers into subgroups with lesser and greater responses to cigarette smoking, even though these subgroups are indistinguishable by clinical criteria. This identifies a group of smokers with a “COPD-like” SAE transcriptome. Comparison of the transcriptome of small airway epithelium in healthy non-smokers, healthy smokers and smokers with COPD. One hundred and fifty-seven samples from several Series were compared.
Project description:The epithelium of the pulmonary airway is specially differentiated to provide defense against environmental insults, but also subject to dysregulated differentiation that results in lung disease. The current paradigm for airway epithelial differentiation is a one-step program whereby a p63+ basal epithelial progenitor cell generates a ciliated or secretory cell lineage, but the cue for this transition and whether there are intermediate steps is poorly defined. Here we identify transcription factor Myb as a key regulator that permits early multilineage differentiation of airway epithelial cells. Myb+ cells were identified as p63– and therefore distinct from basal progenitor cells, but were still negative for markers of differentiation. Myb RNAi treatment of primary-culture airway epithelial cells and Myb gene deletion in mice resulted in a p63– population with failed maturation of Foxj1+ ciliated cells, as well as Scbg1a1+ and Muc5ac+ secretory cells. Consistent with these findings, analysis of whole genome expression of Myb-deficient cells identified Myb-dependent programs for ciliated and secretory cell differentiation. Myb+ cells were rare in human airways but were increased in regions of ciliated cells and mucous cell hyperplasia in samples from subjects with chronic obstructive pulmonary disease. Together, the results show that a p63– Myb+ population of airway epithelial cells represents a distinct intermediate stage of differentiation that is required under normal conditions and may be heightened in airway disease. 12 samples, 2x2 factorial design, factor 1: time (days post-ALI), factor 2:shRNA (Myb vs Scrambled Control), performed in triplicate (biological replicates)
Project description:Smoking is associated with increased airway histamine responsiveness and elevated histamine levels. Transcript levels of histidine decarboxylase (HDC; histamine synthesis) and histamine N-methyltransferase (HNMT; histamine degradation) were evaluated in small airway epithelial (SAE) cells obtained from smokers or non-smokers. Histamine+ SAE cells increased in smokers compared to nonsmokers (p< 0.03). HDC transcript levels were elevated in smokers compared with non-smokers when comparing both bulk RNA from SAE (p< 0.03) and single cell HDC transcripts in mast cells (p<10-6). Elevated HDC transcript levels in mast cells corre-lated with elevated IL33 transcript levels in smoker SAE basal cells, and elevated transcript levels of the IL33 receptor, IL1RL1, in mast cells. In contrast to HDC, transcript levels of HNMT were decreased (p<10-4) in smoker SAE. Significant decreases in HNMT transcript levels were found broadly across SAE differentiated cell types. An in vitro SAE culture model treated with cigarette smoke extract reduced HNMT transcript levels (p<0.05). Together, the data suggests that smoking results in an accumulation of mast cells, elevated expression of histamine-synthesizing mast cell HDC, and a decrease in histamine-degrading HNMT transcript levels broadly in the epithelium. These smoking induced changes are likely contributors to elevated histamine levels in the airways of smokers.
Project description:The airway epithelium is composed of diverse cell types with specialized functions that mediate homeostasis and protect against respiratory pathogens. Human airway epithelial cultures at air-liquid interface (HAE) are a physiologically relevant in vitro model of this heterogeneous tissue, enabling numerous studies of airway disease. HAE cultures are classically derived from primary epithelial cells, the relatively limited passage capacity of which can limit experimental methods and study designs. BCi-NS1.1, a previously described and widely used basal cell line engineered to express hTERT, exhibits extended passage lifespan while retaining capacity for differentiation to HAE. However, gene expression and innate immune function in HAE derived from BCi-NS1.1 versus primary cells have not been fully characterized. Here, combining single cell RNA-Seq (scRNA-Seq), immunohistochemistry, and functional experimentation, we confirm at high resolution that BCi-NS1.1 and primary HAE are largely similar in morphology, cell type composition, and overall transcriptional patterns. While we observed cell-type specific expression differences of several interferon stimulated genes in BCi-NS1.1 HAE cultures, we did not observe significant differences in susceptibility to infection with influenza A virus and Staphylococcus aureus. Taken together, our results further support the BCi-NS1.1 cell line as a valuable tool for the study of airway infectious disease.
Project description:The first changes associated with smoking are in the small airway epithelium (SAE). Given that smoking alters SAE gene expression, but only a fraction of smokers develop chronic obstructive pulmonary disease (COPD), we hypothesized that assessment of SAE genome-wide gene expression would permit biologic phenotyping of the smoking response, and that a subset of healthy smokers would have a “COPD-like” SAE transcriptome. SAE (10th-12th generation) was obtained via bronchoscopy of healthy nonsmokers, healthy smokers and COPD smokers and microarray analysis was used to identify differentially expressed genes. Individual responsiveness to smoking was quantified with an index representing the % of smoking-responsive genes abnormally expressed (ISAE), with healthy smokers grouped into “high” and “low” responders based on the proportion of smoking-responsive genes up- or down-regulated in each smoker. Smokers demonstrated significant variability in SAE transcriptome with ISAE ranging from 2.9 to 51.5%. While the SAE transcriptome of “low” responder healthy smokers differed from both “high” responders and smokers with COPD, the transcriptome of the “high” responder healthy smokers was indistinguishable from COPD smokers. The SAE transcriptome can be used to classify clinically healthy smokers into subgroups with lesser and greater responses to cigarette smoking, even though these subgroups are indistinguishable by clinical criteria. This identifies a group of smokers with a “COPD-like” SAE transcriptome.