title: Can lineage-specific markers be identified to characterize mesenchyme-derived cell populations in the human airways?
abstract: Mesenchyme-derived cells in the airway wall including airway smooth muscle cells, fibroblasts, and myofibroblasts are known to play important roles in airway remodeling. The lack of specific phenotypical markers makes it difficult to define these cell populations in primary cultures. Most relevant studies to date have used animal airway tissues, vascular tissues, or transformed cell lines with only limited studies attempting to phenotypically characterize human airway mesenchymal cells. The objectives of this study were to evaluate reported markers and identify novel markers to define these cell types. We could not identify any specific marker to define these cell populations in vitro that permitted unequivocal identification using immunocytochemistry. However, characteristic filamentous alpha-smooth muscle actin distribution was observed in a significant ( approximately 25%) proportion of human airway smooth muscle cells, whereas this was not observed in airway fibroblasts. A significantly higher proportion of airway fibroblasts expressed alpha(1)- and alpha(2)-integrin receptors compared with human airway smooth muscle cells as assessed by fluorescence activated cell sorting. Global gene expression profiling identified aldo-keto reductase 1C3 (AKR1C3) and cathepsin K as being novel markers to define airway smooth muscle cells, whereas integrin-alpha(8) (ITGA8) and thromboxane synthase 1 (TBXAS1) were identified as novel airway fibroblast-specific markers, and these findings were validated by RT-PCR. Ex vivo studies in human airway tissue sections identified high-molecular weight caldesmon and alpha-smooth muscle actin as being expressed in smooth muscle bundles, whereas ITGA8 and TBXAS1 were absent from these.
authors.affiliation: Univ. of Nottingham, Queen's Medical Centre, UK.
authors.forename: Shailendra R
authors.initials: SR
authors.lastname: Singh
authors.forename: Charlotte K
authors.initials: CK
authors.lastname: Billington
authors.forename: Ian
authors.initials: I
authors.lastname: Sayers
authors.forename: Ian P
authors.initials: IP
authors.lastname: Hall
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000074425:Aldo-Keto Reductase Family 1 Member C3; D015415:Biomarkers / Q000378:metabolism; D001980:Bronchi / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D056657:Cathepsin K / Q000378:metabolism; D019070:Cell Lineage / Q000502:physiology*; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005347:Fibroblasts / Q000737:chemistry*; D005434:Flow Cytometry; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000378:metabolism; D007150:Immunohistochemistry; D039001:Integrin alpha Chains / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000737:chemistry*; D032389:Myocytes, Smooth Muscle / Q000737:chemistry*; D013930:Thromboxane-A Synthase / Q000378:metabolism
chemical_list: D000199:Actins; D015415:Biomarkers; D002148:Calmodulin-Binding Proteins; D016895:Culture Media, Serum-Free; D039001:Integrin alpha Chains; C093856:integrin alpha8; D015096:3-Hydroxysteroid Dehydrogenases; D006911:Hydroxyprostaglandin Dehydrogenases; C487341:AKR1C3 protein, human; D000074425:Aldo-Keto Reductase Family 1 Member C3; D056657:Cathepsin K; D013930:Thromboxane-A Synthase