title: Ca2+ induced surfactant secretion in alveolar type II cultures isolated from the H-2Kb-tsA58 transgenic mouse.
abstract: OBJECTIVE
  There is a need for the development of transgenic mice to elucidate molecular mechanisms in surfactant secretion. However at present very little is known about the regulation of surfactant exocytosis in murine alveolar type II (AT II) cells.
  
  
  METHODS
  We brought AT II cells isolated from the Immorto mouse into culture at 33 degrees C, in the presence of interferon, to generate immortal mouse AT II cells (iMAT II). Surfactant secretion was measured using real-time fluorescence imaging.
  
  
  RESULTS
  iMAT II cells stained with lysotracker green (LTG), a dye specific for lamellar body related vesicles in rat AT II cells. Expression of densely layered structures, characteristic of LBs, was confirmed by transmission electron microscopy. Flash photolysis of caged Ca2+, which specifically elevates intracellular Ca2+ concentration ([Ca2+]i), resulted in LB fusion to the plasma membrane, as analysed using the lipid staining dye FM 1-43. Purinergic stimulation with ATP (10 microM), also resulted in a rise in [Ca2+]i (measured by fura-2), which was followed by LB fusion.
  
  
  CONCLUSIONS
  iMATII cells maintain the expression of LBs over several passages. Surfactant secretion in these cells is regulated by [Ca2+]i, and exhibits similar characteristics to that of rat AT II cells. These cells will be beneficial in studying the impact of genetic modifications on regulated surfactant secretion.
authors.affiliation: Department of Physiology, Innsbruck Medical University, Innsbruck, Austria. paul.jennings@uibk.ac.at
authors.forename: Paul
authors.initials: P
authors.lastname: Jennings
authors.forename: Cristina
authors.initials: C
authors.lastname: Bertocchi
authors.forename: Manfred
authors.initials: M
authors.lastname: Frick
authors.forename: Thomas
authors.initials: T
authors.lastname: Haller
authors.forename: Walter
authors.initials: W
authors.lastname: Pfaller
authors.forename: Paul
authors.initials: P
authors.lastname: Dietl
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D018929:Cell Culture Techniques; D048430:Cell Shape; D002478:Cells, Cultured; D005089:Exocytosis; D005260:Female; D005456:Fluorescent Dyes; D006183:H-2 Antigens / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D013501:Surface-Active Agents / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D011663:Pulmonary Surfactants; D013501:Surface-Active Agents; D002118:Calcium