title: Participation of integrin α5β1 in the fibronectin-mediated adherence of enteroaggregative Escherichia coli to intestinal cells.
abstract: Adherence to the intestinal epithelia is a key feature in enteroaggregative Escherichia coli (EAEC) infection. The aggregative adherence fimbriae (AAFs) are involved in EAEC interaction with receptors at the surface of intestinal cells. We and others have demonstrated that fibronectin is a receptor for AAF/II fimbriae. Considering that the major cellular receptor of fibronectin is integrin α5β1, in this study we evaluated the participation of this receptor in the fibronectin-mediated adherence of EAEC strain 042 to intestinal cells. We found that EAEC strain 042 has the ability to bind directly and indirectly to integrin α5β1; direct binding was not mediated by AAF/II fimbriae and indirect binding was mediated by AAF/II and fibronectin. Coimmunoprecipitation assays confirmed the formation of the complex AafA/fibronectin/integrin α5β1. To evaluate EAEC adherence to intestinal cells, T84 cells were incubated with fibronectin and an antibody that blocks the interaction region of integrin α5β1 to fibronectin, the RGD site. Under these conditions, we found the number of adherent bacteria to epithelial cells significantly reduced. Additionally, fibronectin-mediated adherence of EAEC strain 042 was abolished in HEp-2 cells transfected with integrin α5 shRNA. Altogether, our data support the involvement of integrin α5β1 in the fibronectin-mediated EAEC binding to intestinal cells.
authors.affiliation: Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Dr. Luis Calvo Mackenna, Facultad de Medicina, Universidad de Chile, Antonio Varas 360, Providencia, 7500539 Santiago, Chile.
authors.forename: Mariana
authors.initials: M
authors.lastname: Izquierdo
authors.affiliation: Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Dr. Luis Calvo Mackenna, Facultad de Medicina, Universidad de Chile, Antonio Varas 360, Providencia, 7500539 Santiago, Chile.
authors.forename: Alejandra
authors.identifier: 0000-0001-6715-4045
authors.initials: A
authors.lastname: Alvestegui
authors.affiliation: Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
authors.forename: James P
authors.initials: JP
authors.lastname: Nataro
authors.affiliation: Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ruiz-Perez
authors.affiliation: Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Dr. Luis Calvo Mackenna, Facultad de Medicina, Universidad de Chile, Antonio Varas 360, Providencia, 7500539 Santiago, Chile.
authors.forename: Mauricio J
authors.initials: MJ
authors.lastname: Farfan
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D002460:Cell Line; D020895:Enterocytes / Q000166:cytology / Q000502:physiology*; D004926:Escherichia coli / Q000166:cytology / Q000502:physiology*; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism*
chemical_list: D005353:Fibronectins; D039081:Integrin alpha5beta1