title: IL-13 R110Q, a Naturally Occurring IL-13 Polymorphism, Confers Enhanced Functional Activity in Cultured Human Bronchial Smooth Muscle Cells.
abstract: OBJECTIVE
  Interleukin (IL)-13, a Th2-type cytokine, plays a pivotal role in the pathogenesis of asthma through its direct effects on airway smooth muscles. A naturally occurring IL-13 polymorphism, R110Q, is strongly associated with increased total serum IgE levels and asthma. In the present study, we aimed to determine whether the IL-13 R110Q variant would display different biochemical properties or altered functions in comparison with wild-type (WT) IL-13 in cultured human bronchial smooth muscle cells (hBSMCs).
  
  
  METHODS
  Culture supernatants and cell proteins were collected from cultured hBSMCs that were treated with 50 ng/mL IL-13 or IL-13 R110Q for 24 hours. Eotaxin released into hBSMC culture medium was determined by ELISA. The expression levels of the high-affinity IgE receptor (FcεRI) α-chain, smooth muscle-specific actin alpha chain (α-SMA), smooth muscle myosin heavy chain (SmMHC), and calreticulin in the cells were measured on Western blots.
  
  
  RESULTS
  Compared with WT IL-13, treatment with the IL-13 R110Q variant resulted in a significant increase in eotaxin release as well as significant, although modest, increases in the expression levels of α-SMA, SmMHC, calreticulin, and FcεRI α-chain.
  
  
  CONCLUSIONS
  The results of the present study suggenst that the IL-13 R110Q variant may enhance enhanced functional activities in hBSMCs.
authors.affiliation: Department of Pediatrics, Xinhua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Ya-Fang
authors.initials: YF
authors.lastname: He
authors.forename: Li
authors.initials: L
authors.lastname: Hua
authors.forename: Yi-Xiao
authors.initials: YX
authors.lastname: Bao
authors.forename: Quan-Hua
authors.initials: QH
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Chu
authors.forename: Ding-Zhu
authors.initials: DZ
authors.lastname: Fang
keywords: IL-13; bronchial smooth muscle cells; functional activity; polymorphisms