title: Identification of transcription factors regulating CTNNAL1 expression in human bronchial epithelial cells.
abstract: Adhesion molecules play important roles in airway hyperresponsiveness or airway inflammation. Our previous study indicated catenin alpha-like 1 (CTNNAL1), an alpha-catenin-related protein, was downregulated in asthma patients and animal model. In this study, we observed that the expression of CTNNAL1 was increased in lung tissue of the ozone-stressed Balb/c mice model and in acute ozone stressed human bronchial epithelial cells (HBEC). In order to identify the possible DNA-binding proteins regulating the transcription of CTNNAL1 gene in HBEC, we designed 8 oligo- nucleotide probes corresponding to various regions of the CTNNAL1 promoter in electrophoretic mobility shift assays (EMSA). We detected 5 putative transcription factors binding sites within CTNNAL1 promoter region that can recruit LEF-1, AP-2α and CREB respectively by EMSA and antibody supershift assay. Chromatin immunoprecipitation (ChIP) assay verified that AP-2 α and LEF-1 could be recruited to the CTNNAL1 promoter. Therefore we further analyzed the functions of putative AP-2 and LEF-1 sites within CTNNAL1 promoter by site-directed mutagenesis of those sites within pGL3/FR/luc. We observed a reduction in human CTNNAL1 promoter activity of mutants of both AP-2α and LEF-1 sites. Pre-treatment with ASOs targeting LEF-1and AP-2α yielded significant reduction of ozone-stress-induced CTNNAL1 expression. The activation of AP-2α and LEF-1, followed by CTNNAL1 expression, showed a correlation during a 16-hour time course. Our data suggest that a robust transcriptional CTNNAL1 up-regulation occurs during acute ozone-induced stress and is mediated at least in part by ozone-induced recruitments of LEF-1 and AP-2α to the human CTNNAL1 promoter.
authors.affiliation: Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiang
authors.forename: Xiao-Qun
authors.initials: XQ
authors.lastname: Qin
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Liu
authors.forename: Yu-Rong
authors.initials: YR
authors.lastname: Tan
authors.forename: Chi
authors.initials: C
authors.lastname: Liu
authors.forename: Cai-Xia
authors.initials: CX
authors.lastname: Liu
mesh_terms: D000818:Animals; D001665:Binding Sites; D001980:Bronchi / Q000166:cytology*; D004268:DNA-Binding Proteins; D004847:Epithelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010126:Ozone / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D013312:Stress, Physiological / Q000235:genetics; D050656:Transcription Factor AP-2 / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000502:physiology*; D051178:alpha Catenin / Q000235:genetics*
chemical_list: C495274:CTNNAL1 protein, human; D004268:DNA-Binding Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D051178:alpha Catenin; D010126:Ozone