Isolation, Fractionation and Functional Analysis

of Airway Progenitor Cells

Bronchiolar stem cells have been defined in vivo primarily using functional assays that rely upon their resistance to chemical injury and localization to discrete airway microenvironments. Our findings and those of others suggest that stem cell maintenance and the behavior of other progenitor cell types (Clara cells) is dependent upon local microenvironmental cues. The challenge has been to develop strategies that allow identification of these cells following enzymatic dissociation of lung tissue, a process that results in loss of spatial cues and the regulatory influence that microenvironmental factors have on stem/progenitor cell behavior. In order to extrapolate our in vivo findings to isolated airway cells we have taken advantage of unique mouse models (See mouse models) allowing lineage tagging or manipulation of airway stem and progenitor cell populations. Using this strategy we have established fractionation methods allowing independent enrichment of bronchiolar stem cells and facultative progenitor (Clara) cells (See Teisanu et al., 2008 in references).  Fractionated cells are being used to define new molecular markers that distinguish airway stem/progenitor cell types and for the validation of in vitro and transplantation assays to understand mechanisms regulating self-renewal and differentiation. Validated in vitro and transplantation assays are being used to define stem/progenitor cell behavior within fractionated preparations of isolated human bronchial and bronchiolar epithelial cells in collaboration with members of the National Heart, Lung and Blood Institute-funded Duke/UNC/Pittsburgh/NJMC Lung Cell Therapy consortium.