title: Enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) regulate Wnt/β-catenin-driven trans-differentiation of murine alveolar epithelial cells.
abstract: The alveolar epithelium represents a major site of tissue destruction during lung injury. It consists of alveolar epithelial type I (ATI) and type II (ATII) cells. ATII cells are capable of self-renewal and exert progenitor function for ATI cells upon alveolar epithelial injury. Cell differentiation pathways enabling this plasticity and allowing for proper repair, however, are poorly understood. Here, we applied proteomics, expression analysis and functional studies in primary murine ATII cells to identify proteins and molecular mechanisms involved in alveolar epithelial plasticity. Mass spectrometry of cultured ATII cells revealed a reduction of carbonyl reductase 2 (CBR2) and an increase in enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) protein expression during ATII-to-ATI cell trans-differentiation. This was accompanied by increased Wnt/β-catenin signaling, as analyzed by qRT-PCR and immunoblotting. Notably, ENO1 and PDIA3, along with T1α (podoplanin; an ATI cell marker), exhibited decreased protein expression upon pharmacological and molecular Wnt/β-catenin inhibition in cultured ATII cells, whereas CBR2 levels were stabilized. Moreover, we analyzed primary ATII cells from mice with bleomycin-induced lung injury, a model exhibiting activated Wnt/β-catenin signaling in vivo. We observed reduced CBR2 significantly correlating with surfactant protein C (SFTPC), whereas ENO1 and PDIA3 along with T1α were increased in injured ATII cells. Finally, siRNA-mediated knockdown of ENO1, as well as PDIA3, in primary ATII cells led to reduced T1α expression, indicating diminished cell trans-differentiation. Our data thus identified proteins involved in ATII-to-ATI cell trans-differentiation and suggest a Wnt/β-catenin-driven functional role of ENO1 and PDIA3 in alveolar epithelial cell plasticity in lung injury and repair.
authors.affiliation: Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Mutze
authors.affiliation: Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Vierkotten
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, PA 15213-258, USA.
authors.forename: Jadranka
authors.initials: J
authors.lastname: Milosevic
authors.affiliation: Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Eickelberg
authors.affiliation: Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany melanie.koenigshoff@helmholtz-muenchen.de.
authors.forename: Melanie
authors.initials: M
authors.lastname: Königshoff
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D056809:Alveolar Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001761:Bleomycin; D002460:Cell Line; D054338:Cell Transdifferentiation; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D055785:Gene Knockdown Techniques; D055370:Lung Injury / Q000139:chemically induced / Q000473:pathology; D008810:Mice, Inbred C57BL; D010751:Phosphopyruvate Hydratase / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D040901:Proteomics; D034741:RNA, Small Interfering / Q000378:metabolism; D060449:Wnt Signaling Pathway; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015415:Biomarkers; D034741:RNA, Small Interfering; D051176:beta Catenin; D001761:Bleomycin; D000429:Alcohol Oxidoreductases; C082628:Cbr2 protein, mouse; C457379:Eno1 protein, mouse; D010751:Phosphopyruvate Hydratase; C513195:Pdia3 protein, mouse; D019704:Protein Disulfide-Isomerases
keywords: Alveolar epithelial cells; Beta-catenin; Differentiation; Fibrosis; Lung injury and repair; Wnt pathway