Protease activated receptor-2 expression and function in asthmatic bronchial smooth muscle

PLoS One. 2014 Feb 13;9(2):e86945. doi: 10.1371/journal.pone.0086945. eCollection 2014.


Asthmatic bronchial smooth muscle (BSM) is characterized by structural remodeling associated with mast cell infiltration displaying features of chronic degranulation. Mast cell-derived tryptase can activate protease activated receptor type-2 (PAR-2) of BSM cells. The aims of the present study were (i) to evaluate the expression of PAR-2 in both asthmatic and non asthmatic BSM cells and, (ii) to analyze the effect of prolonged stimulation of PAR-2 in asthmatic BSM cells on cell signaling and proliferation. BSM cells were obtained from both 33 control subjects and 22 asthmatic patients. PAR-2 expression was assessed by flow cytometry, western blot and quantitative RT-PCR. Calcium response, transduction pathways and proliferation were evaluated before and following PAR-2 stimulation by SLIGKV-NH2 or trypsin for 1 to 3 days. Asthmatic BSM cells expressed higher basal levels of functional PAR-2 compared to controls in terms of mRNA, protein expression and calcium response. When PAR-2 expression was increased by means of lentivirus in control BSM cells to a level similar to that of asthmatic cells, PAR-2-induced calcium response was then similar in both types of cell. However, repeated PAR-2 stimulations increased the proliferation of asthmatic BSM cells but not that of control BSM cells even following lentiviral over-expression of PAR-2. Such an increased proliferation was related to an increased phosphorylation of ERK in asthmatic BSM cells. In conclusion, we have demonstrated that asthmatic BSM cells express increased baseline levels of functional PAR-2. This higher basal level of PAR-2 accounts for the increased calcium response to PAR-2 stimulation, whereas the increased proliferation to repeated PAR-2 stimulation is related to increased ERK phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asthma / genetics*
  • Asthma / metabolism
  • Asthma / pathology
  • Bronchi / drug effects
  • Bronchi / metabolism
  • Bronchi / pathology
  • Calcium / metabolism
  • Case-Control Studies
  • Cell Movement / drug effects
  • Cell Proliferation
  • Cells, Cultured
  • Extracellular Signal-Regulated MAP Kinases / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Gene Expression Regulation
  • Humans
  • Male
  • Mast Cells / drug effects
  • Mast Cells / metabolism*
  • Mast Cells / pathology
  • Middle Aged
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / metabolism*
  • Muscle, Smooth / pathology
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / metabolism*
  • Myocytes, Smooth Muscle / pathology
  • Oligopeptides / pharmacology
  • Phosphorylation
  • Receptor, PAR-2 / genetics*
  • Receptor, PAR-2 / metabolism
  • Signal Transduction / drug effects
  • Trypsin / pharmacology
  • Tryptases / genetics
  • Tryptases / metabolism


  • Oligopeptides
  • Receptor, PAR-2
  • Extracellular Signal-Regulated MAP Kinases
  • Trypsin
  • Tryptases
  • Calcium

Grant support

This study was supported by a grant from the “Agence Nationale de la Recherche (ANR N°2010 CESA 001 01 (2010-0145))”, France and the “Fondation pour la Recherche Médicale (FRM)”, France; Mrs. Bara was funded by the “Société de Pneumologie de Langue Française”, France. Mrs Jennifer Gillibert-Duplantier was funded by the “Fondation pour la Recherche Médicale (FRM)”.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.