title: Rapid shedding of proinflammatory microparticles by human mononuclear cells exposed to cigarette smoke is dependent on Ca2+ mobilization.
abstract: OBJECTIVE
  Microparticles are membrane vesicles shed by cells upon activation and apoptosis. Agonists capable of inducing microparticle generation include cytokines, bacterial products, P-selectin, histamine. Cigarette smoke extract has also been recognized as an agonist involved in microparticle generation with an apoptosis-dependent mechanism. We investigated the possibility that cigarette smoke extract induces the rapid generation of proinflammatory microparticles by human mononuclear cells with a calcium-dependent mechanism.
  
  
  METHODS
  Human mononuclear cells were exposed to cigarette smoke extract. [Ca(2+)]i mobilization was assessed with the fluorescent probe Fluo-4 NW. Microparticles were quantified with a prothrombinase assay and by flow cytometry. Normal human bronchial epithelial cells and A549 alveolar cells were incubated with cigarette smoke extract-induced microparticles and the generation of ICAM-1, IL-8, and MCP-1 was assessed by ELISA.
  
  
  RESULTS
  Exposure to cigarette smoke extract induced a rapid increase in [Ca(2+)]i mobilization. Microparticle generation was also increased. EGTA, verapamil and the calmodulin inhibitor, W-7, inhibited microparticle generation. Incubation of lung epithelial cells with cigarette smoke extract-induced microparticles increased the expression of proinflammatory mediators.
  
  
  CONCLUSIONS
  Exposure of mononuclear cells to cigarette smoke extract causes a rapid shedding of microparticles with a proinflammatory potential that might add to the mechanisms of disease from tobacco use.
authors.affiliation: Laboratory of Respiratory Cell Biology, Dipartimento di Patologia Chirurgica, Medica, Molecolare e di Area Critica, University of Pisa and Azienda Ospedaliero-Universitaria Pisana, Ospedale di Cisanello, Via Paradisa, 2, 56124, Pisa, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Cordazzo
authors.forename: Silvia
authors.initials: S
authors.lastname: Petrini
authors.forename: Tommaso
authors.initials: T
authors.lastname: Neri
authors.forename: Stefania
authors.initials: S
authors.lastname: Lombardi
authors.forename: Yuri
authors.initials: Y
authors.lastname: Carmazzi
authors.forename: Roberto
authors.initials: R
authors.lastname: Pedrinelli
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Paggiaro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Celi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001980:Bronchi / Q000166:cytology; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D055252:Cell-Derived Microparticles / Q000187:drug effects*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D045424:Complex Mixtures / Q000494:pharmacology*; D004847:Epithelial Cells; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D012906:Smoke
chemical_list: C111835:CCL2 protein, human; C508606:CXCL8 protein, human; D018932:Chemokine CCL2; D045424:Complex Mixtures; C573420:ICAM1 protein, human; D016209:Interleukin-8; D012906:Smoke; D018799:Intercellular Adhesion Molecule-1; D002118:Calcium