title: Upregulation of miR-18a-5p contributes to epidermal necrolysis in severe drug eruptions.
abstract: BACKGROUND
  Toxic epidermal necrolysis (TEN) is a severe drug-induced cutaneous reaction. Although one of the primary histologic features of TEN is keratinocyte apoptosis, its exact mechanism remains unknown.
  
  
  OBJECTIVE
  We investigated the role of microRNAs (miRNAs) in the pathogenesis of severe drug eruptions and evaluated the possibility that miRNA can be a disease marker.
  
  
  METHODS
  miRNAs were extracted from tissues and sera of patients. PCR array analyses were performed to identify pathogenic miRNAs. The results were confirmed with quantitative real-time PCR, in situ hybridization, transient transfection of small interfering RNAs or miRNA mimics into cultured keratinocytes, flow cytometry, immunoblotting, luciferase assay, and immunohistochemistry.
  
  
  RESULTS
  PCR array analysis and real-time PCR using tissue miRNAs demonstrated that the miR-18a-5p level was increased in the skin of patients with TEN in vivo. Transfection of the miR-18a-5p mimic into keratinocytes in vitro resulted in increased apoptotic cell numbers and caspase-9 activity, which were also increased in the skin of patients with TEN. The miR-18a-5p mimic also downregulated the expression of B-cell lymphoma/leukemia-2-like protein 10 (BCL2L10), an anti-intrinsic apoptotic molecule. A luciferase assay with the BCL2L10 3' untranslated region showed BCL2L10 is directly targeted by miR-18a-5p. The protein and mRNA expressions of BCL2L10 were decreased in the skin of patients with TEN. Transfection with BCL2L10 small interfering RNA induced keratinocyte apoptosis and caspase activity. Furthermore, serum miR-18a-5p levels tended to be increased in patients with TEN and were correlated with areas of skin erythema or erosion in patients with drug eruptions.
  
  
  CONCLUSIONS
  Our results indicated that downregulated BCL2L10 caused by miR-18a-5p overexpression mediates intrinsic keratinocyte apoptosis in patients with TEN. Serum miR-18a-5p levels can be a useful disease marker for drug eruptions.
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Ichihara
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Zhongzhi
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan. Electronic address: mjin@kumamoto-u.ac.jp.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Jinnin
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Izuno
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Shimozono
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yamane
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Fujisawa
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Moriya
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fukushima
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ihn
mesh_terms: D017209:Apoptosis / Q000235:genetics; D015415:Biomarkers; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D035683:MicroRNAs / Q000097:blood / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012867:Skin / Q000473:pathology; D013262:Stevens-Johnson Syndrome / Q000235:genetics* / Q000473:pathology
chemical_list: C117144:BCL2-like 10 protein; D015415:Biomarkers; C522576:MIRN18A microRNA, human; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2
keywords: MicroRNA; apoptosis; drug eruption; keratinocyte; serum