Listeria monocytogenes stimulates mucus exocytosis in cultured human polarized mucosecreting intestinal cells through action of listeriolysin O.
When the intracellular pathogen Listeria monocytogenes infects cultured human mucosecreting polarized HT29-MTX cells apically, it induces the stimulation of mucus exocytosis without cell entry. Using a set of isogenic mutants and purified listeriolysin O (LLO), we identified the L. monocytogenes thiol-activated exotoxin LLO as the agonist of mucus secretion. We demonstrated that the LLO-induced mucus exocytosis did not result from the LLO membrane-damaging activity. We found that LLO-induced mucus exocytosis is an event requiring the binding of LLO to a brush border-associated receptor and membrane oligomerization of the exotoxin. By a pharmacological approach, we demonstrated that no regulatory system or intracellular transducing signal known to be involved in control of mucin exocytosis was activated by LLO. Based on the present data, the stimulatory action of LLO on mucin exocytosis could be accounted for either by an unknown signaling system which remains to be determined or by direct action of LLO with the membrane vesicle components involved in the intracellular vesicular transport of mucins.
CJF 94.07 INSERM, Pathogénie Cellulaire et Moléculaire des Microorganismes Entérovirulents, Faculté de Pharmacie Paris XI, F-92296 Châtenay-Malabry, France.
M H
MH
Coconnier
E
E
Dlissi
M
M
Robard
C L
CL
Laboisse
J L
JL
Gaillard
A L
AL
Servin
D001427:Bacterial Toxins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D016764:Cell Polarity; D005089:Exocytosis / Q000502:physiology*; D019073:HT29 Cells; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006460:Hemolysin Proteins; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis; D008089:Listeria monocytogenes / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D008871:Microvilli / Q000378:metabolism; D009093:Mucus / Q000378:metabolism / Q000382:microbiology; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D014774:Virulence
D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D007375:Interleukin-1; D011956:Receptors, Cell Surface; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C038705:hlyA protein, Listeria monocytogenes