Mycoplasma hyopneumoniae increases intracellular calcium release in porcine ciliated tracheal cells.
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.
Park
Seung-Chun
SC
Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA.
Yibchok-Anun
Sirintorn
S
Cheng
Henrique
H
Young
Theresa F
TF
Thacker
Eileen L
EL
Minion
F Chris
FC
Ross
Richard F
RF
Hsu
Walter H
WH
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
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