Induction of suicidal erythrocyte death by listeriolysin from Listeria monocytogenes.
Listeriolysin, the secreted cytolysin of the facultative intracellular bacterium Listeria monocytogenes, is its major virulence factor. Previously, non-lytic concentrations of listeriolysin were shown to induce Ca2+-permeable nonselective cation channels in human embryonic kidney cells. In erythrocytes, Ca2+ entry is followed by activation of K+ channels resulting in K+-exit as well as by membrane scrambling resulting in phosphatidylserine exposure at the cell surface. Phosphatidylserine-exposing erythrocytes are recognized by macrophages, engulfed, degraded and thus cleared from circulating blood. Phosphatidylserine exposure is a key event of eryptosis, the suicidal death of erythrocytes. The present study utilized patch-clamp technique, Fluo3-fluorescence, and annexin V-binding in FACS analysis to determine the effect of listeriolysin on cell membrane conductance, cytosolic free Ca2+ concentration, and phosphatidylserine exposure, respectively. Within 30 minutes, exposure of human peripheral blood erythrocytes to low concentrations of listeriolysin (which were non-hemolytic for the majority of cells) induced a Ca2+-permeable cation conductance in the erythrocyte cell membrane, increased cytosolic Ca2+ concentration, and triggered annexin V-binding. Increase of extracellular K+ concentration blunted, but did not prevent, listeriolysin-induced annexin V-binding. In conclusion, listeriolysin triggers suicidal death of erythrocytes, an effect at least partially due to depletion of intracellular K+. Listeriolysin induced suicidal erythrocyte death could well contribute to the pathophysiology of L. monocytogenes infection.
Föller
Michael
M
Department of Physiology, Eberhard Karls University, Tübingen, Germany.
Shumilina
Ekaterina
E
Lam
Rebecca
R
Mohamed
Walid
W
Kasinathan
Ravi
R
Huber
Stephan
S
Chakraborty
Trinad
T
Lang
Florian
F
D001427:Bacterial Toxins / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D004912:Erythrocytes / Q000166:cytology*; D005453:Fluorescence; D006360:Heat-Shock Proteins / Q000494:pharmacology*; D006460:Hemolysin Proteins / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008089:Listeria monocytogenes; D010718:Phosphatidylserines / Q000378:metabolism; D011188:Potassium / Q000378:metabolism
D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D010718:Phosphatidylserines; C038705:hlyA protein, Listeria monocytogenes; D011188:Potassium