title: Epithelial-mesenchymal transition of A549 cells is enhanced by co-cultured with THP-1 macrophages under hypoxic conditions.
abstract: Epithelial-mesenchymal transition (EMT) is associated with pulmonary fibrosis, including idiopathic pulmonary fibrosis (IPF). In this study, we investigated EMT of human pulmonary epithelial-derived cells (A549). A549 cells was either cultured by itself or co-cultured with THP-1 macrophages under normoxic (21% O2) and hypoxic (2% O2) conditions. We evaluated the presence of EMT by determining the expression of EMT markers, E-cadherin, vimentin, and fibronectin. To determine the role of TGF-β1 and IL-1β in EMT of the A549 cells, we analyzed the effects of blocking their activity with TGF-β1 inhibitor or IL-1β neutralizing antibody respectively. The A549 cells presented EMT when they were co-cultured with THP-1 macrophages. The EMT of the A549 cells co-cultured with THP-1 macrophages was exacerbated under hypoxia. In addition, the EMT were prevented by the addition of TGF-β1 type I receptor kinase inhibitor. The hypoxic condition increased the mRNA levels of TGF-β1 in A549 cells and THP-1 macrophages and that of IL-1β in THP-1 macrophages when each cells were co-cultured. Anti-IL-1β neutralizing antibody attenuated TGF-β1 secretion in co-culture media under hypoxic conditions. Thus, the IL-1β from THP-1 macrophages up-regulated the TGF-β1 from A549 cells and THP-1 macrophages, and then the TGF-β1 from both cells induced and promoted the EMT of A549 cells when they were co-cultured under hypoxia. Together, these results demonstrate that the interaction between type II pneumocytes and macrophages under hypoxia is necessary for the development of pulmonary fibrosis.
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan; Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Sueki
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan. Electronic address: kmatsuda@shinshu-u.ac.jp.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: Department of Health and Medical Sciences, Graduate School of Medicine, Shinshu University, Matsumoto, Japan.
authors.forename: Chinami
authors.initials: C
authors.lastname: Iwashita
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan; Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Taira
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan; Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Nau
authors.initials: N
authors.lastname: Ishimine
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan; Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Shigeto
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawasaki
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Sugano
authors.affiliation: Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan; Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Honda
mesh_terms: D015687:Cell Hypoxia / Q000276:immunology*; D002460:Cell Line; D018920:Coculture Techniques / Q000379:methods; D016207:Cytokines / Q000276:immunology*; D058750:Epithelial-Mesenchymal Transition / Q000276:immunology*; D006801:Humans; D008264:Macrophages / Q000166:cytology* / Q000276:immunology*; D020545:Respiratory Mucosa / Q000166:cytology* / Q000276:immunology*
chemical_list: D016207:Cytokines
keywords: Epithelial–mesenchymal transition; Hypoxia; Idiopathic pulmonary fibrosis; Macrophages; Type II pneumocytes