title: Postnatal development of the bronchiolar club cells of distal airways in the mouse lung: stereological and molecular biological studies.
abstract: Club (Clara) cells are nonciliated secretory epithelial cells present in bronchioles of distal pulmonary airways. So far, no information is available on the postnatal differentiation of club cells by a combination of molecular biological, biochemical, and stereological approaches in the murine lung. Therefore, the present study was designed to investigate the changes in the club cell secretory proteins (CC10, surfactant proteins A, B and D) and club cell abundance within the epithelium of bronchioles of distal airways during the postnatal development of the mouse lung. Perfusion-fixed murine lungs of three developmental stages (newborn, 15-day-old and adult) were used. Frozen, unfixed lungs were used for cryosectioning and subsequent laser-assisted microdissection of bronchiolar epithelial cells and RT-PCR analyses. High resolution analyses of the three-dimensional structures and composition of lung airways were obtained by scanning electron microscopy. Finally, using design-based stereology, the total and average club cell volume and the volume of secretory granules were quantified by light and transmission electron microscopy. Our results reveal that murine club cells are immature at birth and differentiate postnatally. Further, increase of the club cell volume and number of intracellular granules are closely correlated to the total lung volume enlargement. However, secretory granule density was only increased within the first 15 days of postnatal development. The differentiation is accompanied by a decrease in glycogen content, and a close positive relationship between CC10 expression and secretory granule abundance. Taken together, our data are consistent with the concept that the morphological and functional differentiation of club cells is a postnatal phenomenon.
authors.affiliation: Institute for Anatomy and Cell Biology II, Division of Medical Cell Biology, Justus Liebig University, Aulweg 123, D-35385, Giessen, Germany. Srikanth.Karnati@anatomie.med.uni-giessen.de.
authors.forename: Srikanth
authors.initials: S
authors.lastname: Karnati
authors.affiliation: Department of Trauma, Hannover Medical School, Hannover, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Graulich
authors.affiliation: Institute for Anatomy and Cell Biology II, Division of Medical Cell Biology, Justus Liebig University, Aulweg 123, D-35385, Giessen, Germany.
authors.forename: Gani
authors.initials: G
authors.lastname: Oruqaj
authors.affiliation: Institute for Anatomy and Cell Biology II, Division of Medical Cell Biology, Justus Liebig University, Aulweg 123, D-35385, Giessen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Pfreimer
authors.affiliation: Excellence Cluster Cardio-Pulmonary System (ECCPS), Member of the German Center for Lung Research (DZL), Universities of Giessen and Marburg Lung Center (UGMLC), Justus Liebig University Giessen, Giessen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Seimetz
authors.affiliation: Division of Cellular Pneumology, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany and Department of Anesthesiology, University of Lübeck, Lübeck, Germany.
authors.forename: Cordula
authors.initials: C
authors.lastname: Stamme
authors.affiliation: Division of Neonatology and Pediatric Molecular and Personalized Medicine Program, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Mariani
authors.affiliation: Excellence Cluster Cardio-Pulmonary System (ECCPS), Member of the German Center for Lung Research (DZL), Universities of Giessen and Marburg Lung Center (UGMLC), Justus Liebig University Giessen, Giessen, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Weissmann
authors.affiliation: Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany.|Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Mühlfeld
authors.affiliation: Institute for Anatomy and Cell Biology II, Division of Medical Cell Biology, Justus Liebig University, Aulweg 123, D-35385, Giessen, Germany. Eveline.Baumgart-Vogt@anatomie.med.uni-giessen.de.
authors.forename: Eveline
authors.initials: E
authors.lastname: Baumgart-Vogt
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D055745:Bronchioles / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D008297:Male; D008810:Mice, Inbred C57BL; D016612:Paraffin Embedding; D015854:Up-Regulation; D014598:Uteroglobin / Q000378:metabolism
chemical_list: C556390:Scgb1a1 protein, mouse; D014598:Uteroglobin
keywords: BASCs; CC10; Clara; Electron microscopy; Lung; Stereology; Surfactant proteins