Bacterial RTX Toxins Allow Acute ATP Release from Human Erythrocytes Directly through the Toxin Pore

TY - JOUR

T1 - Bacterial RTX Toxins Allow Acute ATP Release from Human Erythrocytes Directly through the Toxin Pore

AU - Skals, Marianne

AU - Bjaelde, Randi G

AU - Reinholdt, Jesper

AU - Poulsen, Knud

AU - Vad, Brian S

AU - Otzen, Daniel

AU - Leipziger, Jens

AU - Praetorius, Helle A

N1 - Copyright © 2014, The American Society for Biochemistry and Molecular Biology.

PY - 2014/7/4

Y1 - 2014/7/4

N2 - ATP is as an extracellular signaling molecule able to amplify the cell lysis inflicted by certain bacterial toxins including the two RTX toxins α hemolysin (HlyA) from E. coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemcomitans. Inhibition of P2X receptors completely blocks the RTX toxin induced hemolysis over a larger concentration range. It is, however, at present not known how the ATP that provides the amplification is released from the attacked cells. Here we show that both HlyA and LtxA trigger acute release of ATP from human erythrocytes that preceded and were not caused by cell lysis. This early ATP release did not occur via previously described ATP-release pathways in the erythrocyte. Both HlyA and LtxA were capable of triggering ATP release in the presence of the pannexin 1 blockers carbenoxolone and probenecid, and the HlyA induced ATP release was found to be similar in erythrocytes from pannexin 1 wild type and knockout mice. Moreover, the voltage dependent anion channel (VDAC) antagonist TRO19622 had no effect on ATP release by either of the toxins. Finally, we showed that both HlyA and LtxA were able to release ATP from ATP-loaded lipid (POPC) vesicles devoid of any erythrocyte channels or transporters. Again we were able to show that this happened in a non-lytic fashion, using calcein-containing vesicles as controls. These data show that both toxins incorporate into lipid vesicles and allow ATP to be released. We suggest that both toxins cause acute ATP-release by letting ATP pass the toxin pores in both human erythrocytes and artificial membranes.

AB - ATP is as an extracellular signaling molecule able to amplify the cell lysis inflicted by certain bacterial toxins including the two RTX toxins α hemolysin (HlyA) from E. coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemcomitans. Inhibition of P2X receptors completely blocks the RTX toxin induced hemolysis over a larger concentration range. It is, however, at present not known how the ATP that provides the amplification is released from the attacked cells. Here we show that both HlyA and LtxA trigger acute release of ATP from human erythrocytes that preceded and were not caused by cell lysis. This early ATP release did not occur via previously described ATP-release pathways in the erythrocyte. Both HlyA and LtxA were capable of triggering ATP release in the presence of the pannexin 1 blockers carbenoxolone and probenecid, and the HlyA induced ATP release was found to be similar in erythrocytes from pannexin 1 wild type and knockout mice. Moreover, the voltage dependent anion channel (VDAC) antagonist TRO19622 had no effect on ATP release by either of the toxins. Finally, we showed that both HlyA and LtxA were able to release ATP from ATP-loaded lipid (POPC) vesicles devoid of any erythrocyte channels or transporters. Again we were able to show that this happened in a non-lytic fashion, using calcein-containing vesicles as controls. These data show that both toxins incorporate into lipid vesicles and allow ATP to be released. We suggest that both toxins cause acute ATP-release by letting ATP pass the toxin pores in both human erythrocytes and artificial membranes.

U2 - 10.1074/jbc.M114.571414

DO - 10.1074/jbc.M114.571414

M3 - Journal article

C2 - 24860098

SN - 0021-9258

VL - 289

SP - 19098

EP - 19109

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

ER -