title: TNF-α production and apoptosis in hepatocytes after Listeria monocytogenes and Salmonella Typhimurium invasion.
abstract: Invasion of hepatocytes by Listeria monocytogenes (LM) and Salmonella Typhimurium (ST) can stimulate tumor necrosis factor alpha (TNF-α) release and induce apoptosis. In this study, we compared the behavior of hepatocytes invaded by three L. monocytogenes serotypes (LM-4a, LM-4b and LM-1/2a) and by ST to understand which bacterium is more effective in the infectious process. We quantified TNF-α release by ELISA, apoptosis rates by annexin V (early apoptosis) and TUNEL (late apoptosis) techniques. The cell morphology was studied too. TNF-α release rate was highest in ST-invaded hepatocytes. ST and LM-1/2a induced the highest apoptosis production rates evaluated by TUNEL. LM-4b produced the highest apoptosis rate measured by annexin. Invaded hepatocytes presented various morphological alterations. Overall, LM-4b and LM-1/2a proved to be the most efficient at cell invasion, although ST adapted faster to the environment and induced earlier hepatocyte TNF-α release.
authors.affiliation: Laboratory of Bacteriology, Department of Infectious Diseases, School of Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil. saniasan@usp.br
authors.forename: Sânia Alves
authors.initials: SA
authors.lastname: dos Santos
authors.forename: Dahir Ramos
authors.initials: DR
authors.lastname: de Andrade Júnior
authors.forename: Dahir Ramos
authors.initials: DR
authors.lastname: de Andrade
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D022781:Hepatocytes / Q000276:immunology / Q000382:microbiology* / Q000648:ultrastructure; D008089:Listeria monocytogenes / Q000472:pathogenicity / Q000502:physiology*; D008854:Microscopy, Electron; D051381:Rats; D017208:Rats, Wistar; D012486:Salmonella typhimurium / Q000472:pathogenicity / Q000502:physiology*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D014409:Tumor Necrosis Factor-alpha