title: Interferon-γ-induced insufficient autophagy contributes to p62-dependent apoptosis of epithelial cells in chronic rhinosinusitis with nasal polyps.
abstract: BACKGROUND
  Autophagy is a lysosomal degradation pathway that is essential for cell survival, differentiation, and homeostasis. This study aimed to investigate the contribution of autophagy to the pathogenesis of CRS with nasal polyps (CRSwNP).
  
  
  METHODS
  The expression of autophagic proteins [microtubule-associated protein 1 light chain 3B (LC3B)-II, autophagy-related proteins (Atg), and Beclin 1], substrate proteins (p62 and ubiquitinated proteins), and apoptotic signaling molecules [cysteine-aspartic protease-3 and cysteine-aspartic protease-8, and poly-ADP-ribose polymerase] in the sinonasal mucosa and nasal epithelial cells (NECs) was detected by immunohistochemistry and Western blotting. Autophagic vacuoles were observed with transmission electron microscopy. BEAS-2B cells and NECs were treated with rapamycin, bafilomycin A1, or various cytokines. In some experiments, cultured NECs were transfected with small interfering RNA targeting p62 (sip62) or Atg5 (siAtg5). Cultured cells were analyzed with Western blotting and flow cytometry.
  
  
  RESULTS
  Although autophagic protein expression and autophagic vacuole formation were increased in both eosinophilic and noneosinophilic CRSwNP, particularly in NECs, there was also an up-regulation of substrate proteins and apoptotic signaling molecules. IFN-γ, but not IL-4, IL-13, or IL-17A, simultaneously enhanced LC3B-II and p62 levels as well as cell apoptosis in BEAS-2B cells and/or normal NECs. Bafilomycin A1 up-regulated the levels of LC3B-II and p62 in polyp NECs and IFN-γ-treated normal NECs. IFN-γ-induced apoptosis of normal NECs was exaggerated by bafilomycin A1 and siAtg5. Sip62 suppressed apoptosis of polyp NECs and IFN-γ-treated NECs. IFN-γ protein levels were increased in both eosinophilic and noneosinophilic CRSwNP.
  
  
  CONCLUSIONS
  IFN-γ induces activated but insufficient autophagy and thus contributes to a degree to p62-dependent apoptosis of NECs in CRSwNP.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: B-F
authors.initials: BF
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: P-P
authors.initials: PP
authors.lastname: Cao
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: Z-C
authors.initials: ZC
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: Z-Z
authors.initials: ZZ
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: J
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: B
authors.initials: B
authors.lastname: Liao
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: Y-K
authors.initials: YK
authors.lastname: Deng
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: X-B
authors.initials: XB
authors.lastname: Long
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: K
authors.initials: K
authors.lastname: Xu
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: M
authors.initials: M
authors.lastname: Zeng
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: X
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R., China.
authors.forename: Z
authors.identifier: http://orcid.org/0000-0002-4168-6702
authors.initials: Z
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D002478:Cells, Cultured; D002908:Chronic Disease; D004847:Epithelial Cells / Q000166:cytology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D009298:Nasal Polyps / Q000150:complications*; D016601:RNA-Binding Proteins / Q000494:pharmacology*; D012220:Rhinitis / Q000150:complications / Q000209:etiology / Q000473:pathology*; D012852:Sinusitis / Q000150:complications / Q000209:etiology / Q000473:pathology*
chemical_list: C118585:P62 protein, human; D016601:RNA-Binding Proteins; D007371:Interferon-gamma
keywords: apoptosis; autophagy; epithelial cell; interferon-γ; nasal polyps