title: Induction of thymic stromal lymphopoietin expression in 16-HBE human bronchial epithelial cells by 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3.
abstract: Vitamin D exerts profound effects on airway epithelial cells. Thymic stromal lymphopoietin (TSLP) derived from airway epithelial cells plays a role in the innate and antigen‑specific adaptive immune responses. However, the effect of vitamin D on TSLP expression in airway epithelial cells is unclear. In this study, 16-HBE human bronchial epithelial (HBE) cells were cultured with various concentrations of 25-hydroxyvitamin D(3) (25 D(3)) and 1,25-dihydroxyvitamin D(3) (1,25 D(3)). The expression of TSLP in the 16-HBE human bronchial epithelial cell line was analyzed by PCR and enzyme-linked immunosorbent assay (ELISA). We found that the 16-HBE cells converted inactive 25 D(3) to active 1,25 D(3) and that TSLP mRNA and protein expression levels were significantly increased, peaking at 2 or 12 h in the cells exposed to 500 nM 25 D(3) and 50 nM 1,25 D(3) respectively. Since vitamin D(3) upregulated protein 1 (VDUP1) plays a multifunctional role in a variety of cellular responses, we hypothesized that VDUP1 is involved in the induction of TSLP production by 25 D(3). The results showed that the mRNA and protein levels of VDUP1 were significantly upregulated by vitamin D. Furthermore, the silencing of VDUP1 by small interfering RNA (siRNA) significantly inhibited the 25 D(3)- and 1,25 D(3)-mediated induction of TSLP expression. To characterize the metabolic properties of vitamin D in airway epithelial biology, we used the chemical inhibitor of 1α-hydroxylase, itraconazole. The results revealed that itraconazole (10-6 M) reduced the 25 D(3)- but not the 1,25 D(3)-induced TSLP expression in 16-HBE cells. Based on these data, it can be concluded that vitamin D increases TSLP expression in 16-HBE cells through the VDUP1 pathway, which suggests a novel mechanism by which vitamin D alters immune function in the lungs.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Chronic Airways Diseases Laboratory, Nanfang Hospital, Guangzhou, Guangdong 510515, P.R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Chenghua
authors.initials: C
authors.lastname: Peng
authors.forename: Haijin
authors.initials: H
authors.lastname: Zhao
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhang
authors.forename: Hangming
authors.initials: H
authors.lastname: Dong
authors.forename: Jiafu
authors.initials: J
authors.lastname: Song
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhou
authors.forename: Shaoxi
authors.initials: S
authors.lastname: Cai
authors.forename: Fei
authors.initials: F
authors.lastname: Zou
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000037:antagonists & inhibitors; D002112:Calcifediol / Q000494:pharmacology*; D002352:Carrier Proteins / Q000235:genetics; D002461:Cell Line, Transformed; D002762:Cholecalciferol / Q000031:analogs & derivatives* / Q000494:pharmacology; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D020868:Gene Silencing; D006801:Humans; D034622:RNA Interference; D020545:Respiratory Mucosa / Q000187:drug effects / Q000378:metabolism*; D000094632:Thymic Stromal Lymphopoietin
chemical_list: C560304:1,25-dihydroxy-26-(hydroxymethyl)vitamin D3; D002352:Carrier Proteins; D016207:Cytokines; C486715:TXNIP protein, human; D002762:Cholecalciferol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002112:Calcifediol; D000094632:Thymic Stromal Lymphopoietin