title: Mycoplasma hyopneumoniae increases intracellular calcium release in porcine ciliated tracheal cells.
abstract: We investigated the effects of intact pathogenic Mycoplasma hyopneumoniae, nonpathogenic M. hyopneumoniae, and Mycoplasma flocculare on intracellular free Ca2+ concentrations ([Ca2+]i) in porcine ciliated tracheal epithelial cells. The ciliated epithelial cells had basal [Ca2+]i of 103 +/- 3 nM (n = 217 cells). The [Ca2+]i increased by 250 +/- 19 nM (n = 47 cells) from the basal level within 100 s of the addition of pathogenic M. hyopneumoniae strain 91-3 (300 microg/ml), and this increase lasted approximately 60 s. In contrast, nonpathogenic M. hyopneumoniae and M. flocculare at concentrations of 300 microg/ml failed to increase [Ca2+]i. In Ca2+-free medium, pathogenic M. hyopneumoniae still increased [Ca2+]i in tracheal cells. Pretreatment with thapsigargin (1 microM for 30 min), which depleted the Ca2+ store in the endoplasmic reticulum, abolished the effect of M. hyoneumoniae. Pretreatment with pertussis toxin (100 ng/ml for 3 h) or U-73122 (2 microM for 100 s), an inhibitor of phospholipase C, also abolished the effect of M. hyopneumoniae. The administration of mastoparan 7, an activator of pertussis toxin-sensitive proteins G(i) and G(o), increased [Ca2+]i in ciliated tracheal cells. These results suggest that pathogenic M. hyopneumoniae activates receptors that are coupled to G(i) or G(o), which in turn activates a phospholipase C pathway, thereby releasing Ca2+ from the endoplasmic reticulum. Thus, an increase in Ca2+ may serve as a signal for the pathogenesis of M. hyopneumoniae.
authors.affiliation: Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Seung-Chun
authors.initials: SC
authors.lastname: Park
authors.forename: Sirintorn
authors.initials: S
authors.lastname: Yibchok-Anun
authors.forename: Henrique
authors.initials: H
authors.lastname: Cheng
authors.forename: Theresa F
authors.initials: TF
authors.lastname: Young
authors.forename: Eileen L
authors.initials: EL
authors.lastname: Thacker
authors.forename: F Chris
authors.initials: FC
authors.lastname: Minion
authors.forename: Richard F
authors.initials: RF
authors.lastname: Ross
authors.forename: Walter H
authors.initials: WH
authors.lastname: Hsu
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology; D009174:Mycoplasma / Q000472:pathogenicity*; D037342:Pertussis Toxin; D011760:Pyrrolidinones / Q000494:pharmacology; D013552:Swine; D019284:Thapsigargin / Q000494:pharmacology; D014132:Trachea / Q000166:cytology / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D004963:Estrenes; D011760:Pyrrolidinones; D010566:Virulence Factors, Bordetella; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium