Surprisingly, little is known about the impact of thimerosal on immune cell functions

variety of studies have shown that BSM mass is increased, particularly in severe asthma. Such an Chebulinic acid increased BSM mass has been associated with a decrease in lung function, and related with an increased BSM cell proliferation through a mitochondrial-dependent pathway both in vitro and ex vivo. As for bronchial hyperresponsiveness, PAR agonists, such as tryptase or YKL-40 have been PAR-2 Function in Asthmatic Smooth Muscle Cells shown to induce BSM cell proliferation in vitro mediated by the subtype PAR-2, as PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19650784 demonstrated by pharmacological and RNA interference tools. However, the potential role of PAR-2 in airway remodeling remains largely unknown in asthma. Indeed, whereas the proliferation of asthmatic BSM cells to a wide range of growth factors, present in fetal calf serum, is increased as compared to that of non asthmatic BSM cells in vitro, the proliferative response to a single stimulation of PAR-2 by a specific agonist, such as YKL-40, remains unchanged. Moreover, the effect of repeated PAR-2 stimulation on asthmatic BSM cells, a condition that more closely mimics the clinical situation, remains unknown. In addition, in mild to moderate asthmatic bronchi, PAR-2 expression is increased within the epithelium, whereas that in BSM appears unchanged. Nevertheless, the expression of PAR-2 in the BSM remains unknown both in severe asthma ex vivo and in all asthmatics in vitro. Therefore, in the present study, both asthmatic and non asthmatic BSM cells were used in vitro to evaluate the expression of PAR-2 and the effect of its prolonged stimulation on both calcium and proliferative responses. Bronchial specimens were obtained by either fiberoptic bronchoscopy or lobectomy, as previously described . Data are mean 6 SD. BMI: body mass index. OCS: oral corticosteroid. ICS: inhaled corticosteroid. LABA: long acting beta2 agonist. FEV1: forced expiratory volume in one second. FVC: forced vital capacity. FEF 2575: forced expiratory flow between 25 and 75% of FVC.Lentivirus over-expressing PAR-2 The genomic library clone IRATp970H0715D, containing PAR-2 ORF cDNA was used to amplify the coding sequence of the gene. The obtained PCR fragment was then cloned into a transfer lentiviral plasmid containing a GFP reporter gene. As described previously, 3 plasmids were then cotransfected in human embryonic kidney cells to produce replication-deficient lentiviral particles. Cell culture Human BSM cells were derived from bronchial specimens, as previously described. Cell purity was assessed by both immunocytochemistry and flow cytometry, on growth arrested cells using serum-free DMEM for 48 h. All experiments were performed on phenotypically confirmed BSM cells between passages 2 and 5. For each experiment, BSM cells originating from the same passage were used in both asthmatic and non asthmatic subjects. A synthetic peptide with a sequence corresponding to the tethered ligand domain of PAR-2 has been employed to experimentally activate PAR-2 without proteolytic cleavage. We also used the reverse peptide VKGILS-NH2 as negative control for SLIGKV-NH2 experiments. Both SLIGKV-NH2 and VKGILSNH2 were used on growth arrested BSM cells at 1024 M and, were changed every 24 h for 1 to 3 days for proliferation, PAR-2 expression, cell transduction and calcium experiments. PAR-2 expression was assessed by flow cytometry, western blot and quantitative RT-PCR as described previously. Microspectrofluorimetric measurement of cytosolic calcium The Ca2+-sensitive fluoresc