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[Ca 2+ ] i oscillations in renal epithelia caused by α‐hemolysin from Escherichia coli require ATP release and P2 receptor mediated signaling
Author(s) -
Christensen Mette G.,
Skals Marianne,
Fagerberg Steen,
Bjaelde Randi G.,
Leipziger Jens,
Praetorius Helle A
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.lb859
Subject(s) - purinergic receptor , ppads , receptor , apyrase , hemolysin , p2 receptor , extracellular , escherichia coli , chemistry , biochemistry , microbiology and biotechnology , biology , biophysics , virulence , gene
Urinary infections are commonly caused by α‐hemolysin (HlyA)‐ producing E. coli . HlyA forms pores in cell membranes that renders the attacked cells permeable to ions and water. In erythrocytes, the effect of HlyA is strongly amplified by purinergic signaling. We hypothesize that HlyA‐induced [Ca 2+ ] i oscillations in renal epithelia is mediated by ATP‐dependent P2 receptor activation. Here we confirm that HlyA, added at a concentration that cause 50% lysis of human erythrocytes, initiate marked [Ca 2+ ] i oscillatory activity in renal epithelia. This was quantified by live cell fluorescence microscopy in both MDCK cells and freshly isolated, murine thick ascending limb. The HlyA‐induced oscillations were reversible and did not cause permanent cell‐damage. These [Ca 2+ ] i oscillations are completely prevented by non‐selective P2‐receptor antagonists (suramin/PPADS) and by ATP‐degradation (apyrase). To confirm these results, we tested the effect of HlyA on ATP‐biosensor cells. In native 132–1N1 that do not express any P2 receptors, HlyA barely caused any changes in [Ca 2+ ] I . Transfection of the cells with a hP2Y 2 receptor resulted in an extensive increase in the [Ca 2+ ] i oscillatory activity, which is also sensitive to P2 receptor antagonists. These results suggest that HlyA triggers ATP‐release from renal epithelia, which via P2 receptor activation is responsible for the HlyA‐induced [Ca 2+ ] i oscillations.