Biology subjects

Orr, J. C.

Publications and source records attributed to Orr, J. C..

7 recordsLinked to original sources

bioRxiv2026

p63 regulates stem cell maintenance and age-associated functional decline in human airway basal cells

Age is a principal risk factor for chronic respiratory diseases. During aging, the airway epithelium undergoes structural and functional changes, including a reduced regenerative capacity. Basal cells act as stem/progenitor cells within the airway epithelium and are known to acquire age-dependent intrinsic defects, such as genomic mutations, transcriptomic changes and declining stem cell potential. However, the molecular mechanisms bridging transcriptomic change and stem cell function are unknown. Here we show that the transcription factor p63, a key regulator of epithelial cell identity, controls airway basal cell progenitor function in vitro and declines in expression with aging. We found impaired in vitro 2D colony and 3D organoid formation potential, as well as reduced culture longevity in primary human nasal basal cells isolated from older adults (>70 years) compared to those from pediatric (<10 years) donors. p63 protein expression was lower in basal cells from older adults and p63-regulated genes were enriched among genes whose expression changed with aging. Overexpression of p63 in older adult basal cells partially rescued progenitor cell functions, while gene knockdown in pediatric cells caused functional deficits. Integrative transcriptomic analyses revealed the network of p63-regulated genes in basal cells and demonstrated similarities in pathway engagement between TP63-knockdown cells and aged epithelium. Thus, while exogenous p63 expression alone could not rejuvenate older adult epithelial cells, p63 has an influential role in declining epithelial stem cell function during airway aging. Defining the upstream mechanisms controlling p63 decline during epithelial aging may reveal novel targets to promote healthy aging and reduce the burden of chronic lung disease.

cell biology↗

bioRxiv2025

Podoplanin expression identifies human airway basal cells with higher progenitor cell potential

Basal cells are key to maintaining and repairing a functioning airway epithelium. Understanding how basal cells maintain normal airways provides a foundation for interpreting their dysfunction in disease states and for the development of novel therapies. The airway epithelium exists in a dynamic state in which basal stem cells replace lost luminal mucosecretory and multiciliated cell types via an intermediate suprabasal cell state. The ability to isolate basal cells with high progenitor cell potential would be beneficial in regenerative medicine applications, but the molecular identity of this population is unclear. Here, we evaluate candidate surface markers to isolate human basal cells. As an individual marker, we found that podoplanin (PDPN) had a favorable sensitivity and specificity compared with integrin alpha 6 (ITGA6) or nerve growth factor receptor (NGFR). We found that KRT5-expressing basal cells could be subdivided into those with high or low PDPN expression; KRT5-negative cells did not express PDPN. In vitro, PDPN-high basal cells had higher colony-forming capacity, increased population doubling potential and formed larger colonies than PDPN-low basal cells. PDPN-high basal cells expressed higher levels of TP63, as well as other genes expressed by quiescent or resting basal cells identified in single cell RNA sequencing studies. PDPN-low basal cells expressed genes associated with a differentiating basal cell state, including KRT4, NOTCH3 and serpin B family genes. Our results demonstrate that PDPN expression can identify basal cells with high progenitor cell potential, enabling high efficiency sorting of airway stem cells.

cell biology↗

bioRxiv2025

WS6 enables scalable ex vivo expansion and gene editing of epithelial basal stem cells

Modeling human epithelial diseases and developing cell-based therapies require robust methods to expand and manipulate epithelial stem and progenitor cells in vitro. Basal stem/progenitor cells from stratified epithelia can be expanded in 3T3-J2 fibroblast feeder cell co-culture systems, and the addition of the ROCK inhibitor Y-27632 enhances proliferation and culture longevity, a phenomenon described as conditional reprogramming. Here, we present a method incorporating the small molecule WS6 to further improve the proliferation and lifespan of cultured epithelial cells from multiple tissues, including airway, skin, and thymus. Cells maintained in this medium ( EpMED; FAD+Y+WS6) retain basal stem/progenitor cell identity and function, including the capacity to differentiate. We demonstrate their capacity to engraft in vivo in a tracheal transplantation model. In a second application, we generate clonal CRISPR-Cas9 genome edited nasal cultures, introducing targeted knockouts of DNAH5 or DNAI2 to create primary ciliary dyskinesia disease models. We anticipate that our method will have broad applications in epithelial cell biology, disease modeling, and regenerative medicine, while reducing reliance on immortalized or cancer cell lines and animal experimentation.

cell biology↗

bioRxiv2024

Compound screening in primary human airway basal cells identifies Wnt pathway activators as potential pro-regenerative therapies

Regeneration of the airway epithelium restores barrier function and mucociliary clearance following lung injury and infection. Basal cells are tissue-resident airway stem cells that enact regeneration, yet the mechanisms regulating their proliferation and differentiation remain incompletely understood. To identify compounds that promote primary human airway basal cell proliferation, we performed phenotype-based compound screening of 1,429 compounds (from the ENZO and Prestwick Chemical libraries) in 384-well format using primary cells transduced with lentiviral luciferase. 16 pro-proliferative compounds validated in independent donor cell cultures, with several hit compounds activating the Wnt signalling pathway. The effects of compounds on proliferation were further explored in concentration-response, colony formation and 3D organoid assays. Structurally and functionally-related compounds that more potently induced both Wnt activation and basal cell proliferation were investigated. One such compound, 1-azakenpaullone, induced Wnt target gene activation and basal cell proliferation in mice in the absence of tracheal injury. Our results demonstrate the pro-proliferative effect of small-molecule Wnt activators on airway basal cells. These findings contribute to the rationale to develop novel approaches to modulate Wnt signalling during airway epithelial repair. Summary statementIshii, Orr and colleagues perform a high-throughput screen of 1,429 compounds in primary human airway epithelial cells, identifying Wnt activating compounds as promoters of proliferation.

cell biology↗

bioRxiv2024

A lentiviral toolkit to monitor airway epithelial cell differentiation using bioluminescence

Basal cells are adult stem cells in the airway epithelium and regenerate differentiated cell populations, including the mucosecretory and ciliated cells that enact mucociliary clearance. Human airway basal cells can proliferate and produce differentiated epithelium in vitro. However, studies of airway epithelial differentiation mostly rely on immunohistochemical or immunofluorescence-based staining approaches, meaning that a quantitative approach is lacking. Here, we use a lentiviral reporter gene approach to transduce primary human basal cells with bioluminescence-based reporter constructs to monitor airway epithelial differentiation longitudinally. We generated three constructs driven by promoter sequences from the TP63, MUC5AC and FOXJ1 genes to quantitatively assess basal cell, ciliated cell and mucosecretory cell abundance, respectively. We validated these constructs by tracking differentiation of basal cells in air-liquid interface and organoid ( bronchosphere) cultures. Transduced cells also responded appropriately to stimulation with interleukin 13 (IL-13; to increase mucosecretory differentiation and mucus production) and IL-6 (to increase ciliated cell differentiation). We anticipate that these constructs will be a valuable resource for researchers monitoring airway epithelial cell differentiation in primary epithelial and/or induced pluripotent stem cell (iPSC) cell cultures. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/579635v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@a4e127org.highwire.dtl.DTLVardef@b9c7c5org.highwire.dtl.DTLVardef@ea7bd0org.highwire.dtl.DTLVardef@66a384_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

Lung viral infection modelling in a bioengineered whole-organ

Lung infections are one of the leading causes of death worldwide, and this situation has been exacerbated by the emergence of COVID-19. Pre-clinical modelling of viral infections has relied on cell cultures that lack 3D structure and the context of lung extracellular matrices. Here, we propose a bioreactor-based, whole-organ lung model of viral infection. The bioreactor takes advantage of an automated system to achieve efficient decellularization of a whole rat lung, and recellularization of the scaffold using primary human bronchial cells. Automatization allowed for the dynamic culture of airway epithelial cells in a breathing-mimicking setup that led to an even distribution of lung epithelial cells throughout the distal regions. In the sealed bioreactor system, we demonstrate proof-of-concept for viral infection with the engineered lung by infecting primary human airway epithelial cells. Moreover, to assess the possibility of drug screening in this model, we demonstrate the efficacy of the broad-spectrum antiviral Remdesivir. This whole-organ scale lung infection model represents a step towards modelling viral infection of human cells in a 3D context, providing a powerful tool to investigate the mechanisms of the early stages of pathogenic infections and the development of effective treatment strategies for respiratory diseases.

bioengineering↗

bioRxiv2020

Cell-intrinsic differences between human airway epithelial cells from children and adults

The airway epithelium is a key protective barrier, the integrity of which is preserved by the self-renewal and differentiation of basal stem cells. Epithelial cells are central to the pathogenesis of multiple lung diseases. In chronic lung diseases, increasing age is a principle risk factor. Few studies have explored the differences between airway epithelial cells in children and adults and how the function of basal stem cells changes during ageing is poorly understood. Here, we analyze airway epithelial cells from children and adults in homeostatic conditions (laser capture-microdissected whole epithelium and fluorescence-activated cell-sorted basal cells) and in proliferation-inducing cell culture conditions. We find that, while the cellular composition of the pediatric and adult tracheobronchial epithelium is broadly similar, in cell culture, pediatric airway epithelial cells displayed higher colony-forming ability, sustained in vitro growth and outcompeted adult cells in competitive proliferation assays. In RNA sequencing experiments, we observed potentially important differences between epithelium from children and adults, including higher baseline interferon-associated gene expression in pediatric epithelium. Our results demonstrate cell-intrinsic differences in transcriptional profile and regenerative capacity between proximal airway epithelial cells of children and adults. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=178 SRC="FIGDIR/small/027144v2_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@b7a680org.highwire.dtl.DTLVardef@1145543org.highwire.dtl.DTLVardef@1e9a86aorg.highwire.dtl.DTLVardef@12fe0bf_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗