title: Differentiation of human alveolar epithelial cells in primary culture: morphological characterization and synthesis of caveolin-1 and surfactant protein-C.
abstract: Human alveolar type II cells were isolated from lung tissue and cultured for several days. The morphology of cells was investigated at different time points postseeding and the synthesis of alveolar cell-type specific proteins was analyzed using different methods. The rationale of the study was to characterize a primary cell culture of human alveolar cells for the development of an in vitro model studying pulmonary drug delivery. In vitro test systems based on human cells are attracting increasing interest as important alternatives to animal-derived models because possible interspecies differences in alveolar cell biology and transport mechanisms cannot be excluded. In our study, both morphological characterization and marker protein synthesis of human alveolar cells in culture indicate the differentiation of isolated alveolar type II cells into epithelial monolayers consisting of alveolar type I-like and alveolar type II-like cells, which corresponds to the composition of the alveolar epithelium of the donor tissue. By using flow cytometry, immunofluorescence, immunoblotting and reverse transcriptase polymerase chain reaction (RT-PCR), we observed a shift in the synthesis of important marker proteins. Early cultures were characterized by low caveolin-1 and high Sp-C levels. In comparison, the protein biosynthesis of alveolar cells switched with time of culture to high caveolin-1 and low Sp-C levels. Based on the similarity between human alveolar epithelium and the development of our primary alveolar cell culture, we suggest that the culture may serve as a suitable model to study epithelial transport or cell biological processes in human alveolar cells.
authors.affiliation: Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Fuchs
authors.forename: Andrew John
authors.initials: AJ
authors.lastname: Hollins
authors.forename: Michael
authors.initials: M
authors.lastname: Laue
authors.forename: Ulrich Friedrich
authors.initials: UF
authors.lastname: Schaefer
authors.forename: Klaus
authors.initials: K
authors.lastname: Roemer
authors.forename: Mark
authors.initials: M
authors.lastname: Gumbleton
authors.forename: Claus-Michael
authors.initials: CM
authors.lastname: Lehr
mesh_terms: D000906:Antibodies; D001692:Biological Transport; D015415:Biomarkers; D051242:Caveolin 1; D022461:Caveolins / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D002454:Cell Differentiation; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D005434:Flow Cytometry; D006801:Humans; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000378:metabolism; D037721:Pulmonary Surfactant-Associated Protein C / Q000032:analysis* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020545:Respiratory Mucosa / Q000166:cytology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000906:Antibodies; D015415:Biomarkers; C495540:CAV1 protein, human; D051242:Caveolin 1; D022461:Caveolins; D037721:Pulmonary Surfactant-Associated Protein C; D012333:RNA, Messenger