title: Long TSLP transcript expression and release of TSLP induced by TLR ligands and cytokines in human keratinocytes.
abstract: BACKGROUND
  Thymic stromal lymphopoietin (TSLP), highly expressed in keratinocytes in atopic dermatitis patients and bronchial epithelial cells in asthma patients, plays a key role in allergic diseases. Two forms of TSLP mRNA (long and short) have been reported.
  
  
  OBJECTIVE
  We compared the expression of the long-form and total TSLP transcripts in primary human keratinocytes.
  
  
  METHODS
  Primary human keratinocytes were stimulated with Toll-like receptor (TLR) ligands, cytokines, and vitamin D receptor agonists. Gene expression was analyzed by quantitative real-time PCR. The amount of TSLP released was measured by ELISA.
  
  
  RESULTS
  PolyI:C (TLR3 ligand), FSL-1 (TLR2-TLR6 ligand) and flagellin (TLR5 ligand) upregulated long-form TSLP expression, which predominantly contributed to upregulation of total TSLP expression. A glucocorticoid or an endosomal acidification inhibitor inhibited the polyI:C-dependent upregulation of total TSLP and the decrease of the total TSLP was due to the decrease of the long-form. An atopic cytokine milieu (TNF-α+IL-4+IL-13) or TNF-α alone also upregulated the long-form. These stimuli also induced the release of TSLP. In contrast, a high concentration of calcitriol (1,25-dihydroxyvitamin D(3), the active form of vitamin D(3)) or its analog MC903 upregulated total TSLP significantly but not the long-form, and did not induce the release of TSLP.
  
  
  CONCLUSIONS
  TLR ligands or cytokines predominantly upregulate the gene expression of the long TSLP form, which contributes to the TSLP protein production, in primary human keratinocytes. Specific measurement of the long-form rather than total TSLP should be useful for accurate detection of functional human TSLP gene expression.
authors.affiliation: Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xie
authors.forename: Toshiro
authors.initials: T
authors.lastname: Takai
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.forename: Ko
authors.initials: K
authors.lastname: Okumura
authors.forename: Hideoki
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D002117:Calcitriol / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D004075:Diglycerides / Q000494:pharmacology; D005408:Flagellin / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008024:Ligands; D009842:Oligopeptides / Q000494:pharmacology; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D018167:Receptors, Calcitriol / Q000819:agonists; D051193:Toll-Like Receptors; D015854:Up-Regulation; D000094632:Thymic Stromal Lymphopoietin
chemical_list: D016207:Cytokines; D004075:Diglycerides; C460864:FSL-1 lipoprotein, synthetic; D008024:Ligands; D009842:Oligopeptides; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D051193:Toll-Like Receptors; D005408:Flagellin; D002117:Calcitriol; D011070:Poly I-C; D000094632:Thymic Stromal Lymphopoietin