title: An avian pathogenic Escherichia coli isolate induces caspase 3/7 activation in J774 macrophages.
abstract: Avian pathogenic Escherichia coli (APEC) strains, the etiological agent of colibacillosis in poultry, must resist the attack of incoming macrophages in order to cause disease. In this work, we show that an APEC strain (APEC17) remained viable inside J774 macrophages for at least 8 h and was cytotoxic to them 6-8 h after infection. APEC17 induced caspase 3/7 activation, the central caspases in apoptosis, in infected macrophages already at 2h after infection. Both cytotoxicity and caspase 3/7 activation were reduced when cells were infected with heat-killed APEC17, showing that bacteria must be viable to induce apoptosis. Our findings using APEC17 suggest that APEC may escape destruction by triggering macrophage apoptotic death.
authors.affiliation: Departamento de Biofísica, Universidade Federal do Rio Grande do Sul, P.O. Box 15005, 91501-970 Porto Alegre, RS, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Bastiani
authors.forename: Marilda Carlos
authors.initials: MC
authors.lastname: Vidotto
authors.forename: Fabiana
authors.initials: F
authors.lastname: Horn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity* / Q000648:ultrastructure; D004927:Escherichia coli Infections / Q000201:enzymology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D007700:Kinetics; D008264:Macrophages / Q000201:enzymology / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008855:Microscopy, Electron, Scanning; D009842:Oligopeptides / Q000737:chemistry; D010587:Phagocytosis; D011200:Poultry; D011201:Poultry Diseases / Q000201:enzymology / Q000382:microbiology / Q000473:pathology; D013379:Substrate Specificity; D014774:Virulence
chemical_list: D009842:Oligopeptides; C505409:Casp3 protein, mouse; C505524:Casp7 protein, mouse; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases