title: Keratin14 mRNA expression in human pneumocytes during quiescence, repair and disease.
abstract: The lung alveoli slowly self-renew pneumocytes, but their facultative regeneration capacity is rapidly efficient after an injury, so fibrosis infrequently occurs. We recently observed Keratin 14 (KRT14) expression during diffuse alveolar damage (DAD), but not in controls. We wonder if KRT14 may be a marker of pneumocyte transition from quiescence to regeneration. Quantitative PCR and Western blot analyses highlighted the presence of KRT14 (mRNA and protein) only in human lung samples with DAD or interstitial lung disease (ILD). In the exponentially growing cell lines A549 and H441, the mRNA and protein levels of KRT14 peaked at day one after cell seeding and decreased at day two, opposite to what observed for the proliferation marker E2F1. The inverse relation of KRT14 versus E2F1 expression holds true also for other proliferative markers, such as cyclin E1 and cyclin D1. Of interest, we also found that E2F1 silencing caused cell cycle arrest and increased KRT14 expression, whilst E2F1 stimulation induced cell cycle progression and decreased KRT14. KRT14 also increased in proliferative pneumocytes (HPAEpiC) just before transdifferentiation. Overall, our results suggest that KRT14 is a viable biomarker of pneumocyte activation, and repair/regeneration. The involvement of KRT14 in regenerative process may suggest a novel pharmaceutical target to accelerate lung repair.
authors.affiliation: Pulmonology Department, University Hospital of Cattinara, Trieste, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Confalonieri
authors.affiliation: Molecular Pathology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Buratti
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Grassi
authors.affiliation: Institute of Pathologic Anatomy, University of Trieste, Trieste, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Bussani
authors.affiliation: Department of Diagnostic and Public Health, Pathology Unit, University of Verona, Verona, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Chilosi
authors.affiliation: Department of Engineering and Architecture, University of Trieste, Trieste, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Farra
authors.affiliation: Department of Engineering and Architecture, University of Trieste, Trieste, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Abrami
authors.affiliation: Molecular Pathology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Stuani
authors.affiliation: Pulmonology Department, University Hospital of Cattinara, Trieste, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Salton
authors.affiliation: Department of Diagnostic and Public Health, Pathology Unit, University of Verona, Verona, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ficial
authors.affiliation: Pulmonology Department, University Hospital of Cattinara, Trieste, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Confalonieri
authors.affiliation: Institute of Pathologic Anatomy, University of Trieste, Trieste, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zandonà
authors.affiliation: Molecular Pathology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.|Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Romano
mesh_terms: D000072283:A549 Cells; D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D056809:Alveolar Epithelial Cells / Q000166:cytology / Q000378:metabolism; D059447:Cell Cycle Checkpoints; D049109:Cell Proliferation; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D050687:E2F1 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D053547:Keratin-14 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D017563:Lung Diseases, Interstitial / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015513:Oncogene Proteins / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D059467:Transcriptome
chemical_list: C530104:CCND1 protein, human; C475820:CCNE1 protein, human; D019927:Cyclin E; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D053547:Keratin-14; D015513:Oncogene Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D019938:Cyclin D1