Abstracts - Deutsche Zoologische Gesellschaft

194 Physiology PostersP PH.16 - ENActivation of Erk-type MAP kinases and induction of c-fos by secretory productsof Staphylococcus aureus in immortalised human airway epithelial cells (S9 and16HBE14o- cells)Sabine Below, Anne Konkel, Jan-Peter HildebrandtLehrstuhl für Physiologie und Biochemie der Tiere, Universität GreifswaldSince bronchial epithelia are major targets for infection by Staphylococcus aureus, we studied effectsof bacterial secretory products on intracellular signalling and early gene regulation in two types ofhuman airway epithelial cells. It is unknown whether Staphylococci affect all types of cells equallyor use specific cell types for adhesion, induction of changes in cell physiology and, finally, for occasionalinvasion of the body. Culture supernatants of S. aureus (COL) from exponential (OD 540nm=1) or stationary growth phases (OD 540nm= 10) or recombinant hemolysins A (rHla) and B (rHlb) wereadded to the culture medium of S9 or HBE cells for 2 h at 37°C. Quantitative Western blot analysisof soluble proteins extracted from these cells showed activation of Erk-type MAP kinases when cellshad been treated with rHlb, a toxin with sphingomyelinase activity, or 10% (v/v) of OD1- or OD10-supernatants. After treatment with rHla, a pore-forming toxin of S. aureus, an activation of Erk1/2occurred in S9, but not in HBE cells. Both S9 and HBE cells developed an induction of c-fos whentreated with rHla which was dependent upon Erk-activation in S9, but not in HBE cells. Activationof Erk1/2 was observed in both cell types upon incubation with rHlb. The results indicate that secretoryproducts of S. aureus affect endogenous cell signalling in airway epithelial cells related to cellgrowth and differentiation in a cell type-specific manner.P PH.17 - ENStaphylococcus aureus-toxins modulate calcium signaling in immortalized humanairway epithelial cellsKaroline Gäbler, Stefanie Eichstaedt, Jan-Peter HildebrandtZoologie, Physiologie und Biochemie der Tiere, Ernst Moritz Arndt-Universität, GreifswaldBronchial epithelia are major targets for Staphylococcus aureus. We studied effects of bacterialsecretory products on calcium signaling in immortalized human airway cells (16HBE14o- and S9).Calcium signals were elicited by activation of phospholipase C-coupled receptors (muscarinic acetylcholinereceptors in S9 cells or purinergic receptors (P2Y 2) in 16HBE14o- cells, respectively).Intracellular calcium concentration was measured using the fluorescent dye Indo-1. Addition of recombinanthemolysin A (rHla), a pore-forming S. aureus-toxin, mediated calcium influx through theplasma membrane. At a concentration of 200 ng/ml rHla, cells seemed to activate Ca 2+ -extrusionwhich resulted in lower plateau values of [Ca 2+ ] iupon receptor activation. At 2000 ng/ml rHla,calcium influx could not be compensated for by calcium extrusion resulting in a steady increase in[Ca 2+ ] i. However, rHla-mediated pores in the plasma membrane seemed to be selective for calciumions and were not permeable to small organic molecules as indicated by experiments using a live/dead cell-stain. In preliminary experiments applying recombinant hemolysin B (rHlb) to the cells,a moderate attenuation of plateau calcium signals was observed in 16HBE14o- cells, while a slightelevation in plateau-[Ca 2+ ] iwas observed in S9 cells. These results indicate that secretory productsof S. aureus affect endogenous calcium signaling in airway epithelial cells and may compromise thebarrier function of the epithelium.