title: Escherichia coli isolates from inflammatory bowel diseases patients survive in macrophages and activate NLRP3 inflammasome.
abstract: Crohn's disease (CD) is a multifactorial pathology associated with the presence of adherent-invasive Escherichia coli (AIEC) and NLRP3 polymorphic variants. The presence of intracellular E. coli in other intestinal pathologies (OIP) and the role of NLRP3-inflammasome in the immune response activated by these bacteria have not been investigated. In this study, we sought to characterize intracellular strains isolated from patients with CD, ulcerative colitis (UC) and OIP, and analyze NLRP3-inflammasome role in the immune response and bactericidal activity induced in macrophages exposed to invasive bacteria. For this, intracellular E. coli isolation from ileal biopsies, using gentamicin-protection assay, revealed a prevalence and CFU/biopsy of E. coli higher in biopsies from CD, UC and OIP patients than in controls. To characterize bacterial isolates, pulsed-field gel electrophoresis (PFGE) patterns, virulence genes, serogroup and phylogenetic group were analyzed. We found out that bacteria isolated from a given patient were closely related and shared virulence factors; however, strains from different patients were genetically heterogeneous. AIEC characteristics in isolated strains, such as invasive and replicative properties, were assessed in epithelial cells and macrophages, respectively. Some strains from CD and UC demonstrated AIEC properties, but not strains from OIP. Furthermore, the role of NLRP3 in pro-inflammatory cytokines production and bacterial elimination was determined in macrophages. E. coli strains induced IL-1β through NLRP3-dependent mechanism; however, their elimination by macrophages was independent of NLRP3. Invasiveness of intracellular E. coli strains into the intestinal mucosa and IL-1β production may contribute to CD and UC pathogenesis.
authors.affiliation: Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: Marjorie
authors.initials: M
authors.lastname: De la Fuente
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.
authors.forename: Luigi
authors.initials: L
authors.lastname: Franchi
authors.affiliation: Disciplinary Program of Microbiology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: Daniela
authors.initials: D
authors.lastname: Araya
authors.affiliation: Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: David
authors.initials: D
authors.lastname: Díaz-Jiménez
authors.affiliation: Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Olivares
authors.affiliation: Gastroenterology Department, Hospital Clínico Pontificia Universidad Católica de Chile, Santiago, CL 6513677, Chile.
authors.forename: Manuel
authors.initials: M
authors.lastname: Álvarez-Lobos
authors.affiliation: Division of Infectious Diseases & Immunology, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Golenbock
authors.affiliation: Cell and Molecular Biology Program, Biomedical Sciences Institute, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: María-Julieta
authors.initials: MJ
authors.lastname: González
authors.affiliation: Laboratory of Oncology and Molecular Genetics, Colorectal Surgery Unit, Clínica Las Condes, Santiago, CL 7591018, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: López-Kostner
authors.affiliation: Gastroenterology Unit, Clínica Las Condes, Santiago, CL 7591018, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Quera
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Núñez
authors.affiliation: Disciplinary Program of Microbiology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile.
authors.forename: Roberto
authors.initials: R
authors.lastname: Vidal
authors.affiliation: Disciplinary Program of Immunology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, CL 8380453, Chile. Electronic address: mhermoso@med.uchile.cl.
authors.forename: Marcela A
authors.initials: MA
authors.lastname: Hermoso
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D058491:Bacterial Load; D001706:Biopsy; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000382:microbiology; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*; D005260:Female; D005838:Genotype; D054884:Host-Pathogen Interactions; D006801:Humans; D007082:Ileum / Q000382:microbiology / Q000473:pathology; D058847:Inflammasomes / Q000378:metabolism*; D015212:Inflammatory Bowel Diseases / Q000382:microbiology*; D008264:Macrophages / Q000382:microbiology*; D008297:Male; D051379:Mice; D050296:Microbial Viability; D008875:Middle Aged; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D037521:Virulence Factors / Q000235:genetics; D055815:Young Adult
chemical_list: D002352:Carrier Proteins; D058847:Inflammasomes; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D037521:Virulence Factors
keywords: Crohn's disease; E. coli; IL-1β; Inflammasome; NLRP3