title: CD45/CD11b positive subsets of adult lung anchorage-independent cells harness epithelial stem cells in culture.
abstract: Compensatory growth is mediated by multiple cell types that interact during organ repair. To elucidate the relationship between stem/progenitor cells that proliferate or differentiate and somatic cells of the lung, we used a novel organotypic ex vivo pneumoexplant system. Applying this technique, we identified a sustained culture of repopulating adult progenitors in the form of free-floating anchorage-independent cells (AICs). AICs did not express integrin proteins α5, β3 and β7, and constituted 37% of the total culture at day 14, yielding a mixed yet conservative population that recapitulated RNA expression patterns of the healthy lung. AICs exhibited rapid proliferation manifested by a marked 60-fold increase in cell numbers by day 21. More than 50% of the AIC population was c-KIT(+) or double-positive for CD45(+) and CD11b(+) antigenic determinants, consistent with cells of hematopoietic origin. The latter subset was found to be enriched with prosurfactant protein-C and SCGB1A1 expressing putative stem cells and with aquaporin-5 producing cells, characteristic of terminally differentiated alveolar epithelial type-1 pneumocytes. At the air/gel interface, AICs undergo remodeling to form a cellular lining, whereas TGF(β)1 treatment modifies protein expression properties to further imply a robust effect of the microenvironment on AIC phenotypic changes. These data confirm the active participation of clonogenic hematopoietic stem cells in a mammalian model of lung repair and validate mixed stem/somatic cell cultures, which license sustained cell viability, proliferation and differentiation, for use in studies of compensatory pulmonary growth.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. yakov.peter@einstein.yu.edu
authors.forename: Yakov
authors.initials: Y
authors.lastname: Peter
authors.forename: Namita
authors.initials: N
authors.lastname: Sen
authors.forename: Elena
authors.initials: E
authors.lastname: Levantini
authors.forename: Steven
authors.initials: S
authors.lastname: Keller
authors.forename: Edward P
authors.initials: EP
authors.lastname: Ingenito
authors.forename: Aaron
authors.initials: A
authors.lastname: Ciner
authors.forename: Robert
authors.initials: R
authors.lastname: Sackstein
authors.forename: Steven D
authors.initials: SD
authors.lastname: Shapiro
mesh_terms: D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology / Q000378:metabolism*; D056809:Alveolar Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D039481:CD11b Antigen; D049109:Cell Proliferation; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000096:biosynthesis; D017493:Leukocyte Common Antigens; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008297:Male
chemical_list: D039481:CD11b Antigen; D016023:Integrins; D017493:Leukocyte Common Antigens; C516770:Ptprc protein, mouse