title: 17β-Estradiol suppresses MHC class I chain-related B gene expression via an intact GC box.
abstract: Major histocompatibility complex class I chain-related B (MICB) is a membrane-bound glycoprotein involved in both innate and adaptive immunity through its interaction with NKG2D receptors present on γδ T, αβ CD8(+) T, and natural killer cells. Factors known to upregulate MICB expression include heat shock, viral or bacterial infection, and tumorigenesis, and here, we explored the effect of 17β-estradiol (E2) on MICB regulation. Physiological concentrations of E2 were found to suppress MICB mRNA and surface protein levels and this effect was antagonized by the antiestrogen ICI 182780. The inhibitory effect of E2 was also observed for other NKG2D ligands, MICA and ULBPs. Evaluation of promoter fragments from the common MICB*00502 allele revealed that inhibition of transcription by E2 required the GC box at -87. The electrophoretic mobility shift assay and supershift analysis established the presence of SP1, SP3, or estrogen receptor α recognition sites within the MICB promoter sequence and interaction of these factors in situ was confirmed by chromatin immunoprecipitation. We conclude that E2 upon forming a complex with its cognate receptor suppresses MICB expression through binding with SP1/SP3 sites within the MICB promoter GC box. These results suggest that the partial benefit of 17β-estradiol on autoimmune diseases may be mediated by reducing the immune NKG2D ligands like MICB.
authors.affiliation: Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Niramai
authors.initials: N
authors.lastname: Sroijak
authors.forename: Mathurose
authors.initials: M
authors.lastname: Ponglikitmongkol
mesh_terms: D056704:Adaptive Immunity; D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D000077267:Fulvestrant; D058851:GPI-Linked Proteins / Q000235:genetics / Q000276:immunology; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000235:genetics / Q000276:immunology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D016329:Sp1 Transcription Factor / Q000235:genetics* / Q000276:immunology; D051705:Sp3 Transcription Factor / Q000235:genetics* / Q000276:immunology
chemical_list: D004965:Estrogen Antagonists; D058851:GPI-Linked Proteins; D015395:Histocompatibility Antigens Class I; C527085:KLRK1 protein, human; C099187:MHC class I-related chain A; C098080:MICB antigen; D055655:NK Cell Lectin-Like Receptor Subfamily K; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; D000077267:Fulvestrant; D004958:Estradiol