title: Toxoplasma gondii Infection Promotes Epithelial Barrier Dysfunction of Caco-2 Cells.
abstract: After oral infection, Toxoplasma gondii invades intestinal cells, induces breakdown of intestinal physiology and barrier functions, and causes intestinal pathology in some animal species. Although parasites' invasion into host cells is a known phenomenon, the effects of T. gondii infection in the intestinal barrier are still not well established. To evaluate morphological and physiological modifications on the colorectal adenocarcinoma-derived Caco-2 cell line during T. gondii infection, microvilli, tight junction integrity, and transepithelial electrical resistance (TEER) were investigated under infection. It was observed that the dextran uptake (endocytosis) and distribution were smaller in infected than in noninfected Caco-2 cells. The infection leads to the partial loss of microvilli at the cell surface. Claudin-1, zonula occludens-1 (ZO-1), and occludin expressions were colocalized by immunofluorescence and presented discontinuous net patterns in infected cells. Immunoblotting analysis at 24 hr postinfection revealed decreasing expression of occludin and ZO-1 proteins, whereas claudin-1 presented similar expression level compared with noninfected cells. T. gondii decreased TEER in Caco-2 cells 24 hr after infection. Our results suggest that T. gondii infection may lead to the loss of integrity of intestinal mucosa, resulting in impaired barrier function.
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
authors.forename: Marisol Pallete
authors.initials: MP
authors.lastname: Briceño
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
authors.forename: Layane Alencar Costa
authors.initials: LA
authors.lastname: Nascimento
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
authors.forename: Nathalia Pires
authors.initials: NP
authors.lastname: Nogueira
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
authors.forename: Paulo Victor Czarnewski
authors.initials: PV
authors.lastname: Barenco
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)|Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
authors.forename: Eloisa Amália Vieira
authors.initials: EA
authors.lastname: Ferro
authors.affiliation: Laboratory of Biomedical Sciences, Federal University of Uberlândia, Ituiutaba, Minas Gerais, Brazil (KR-O)
authors.forename: Karine
authors.initials: K
authors.lastname: Rezende-Oliveira
authors.affiliation: Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
authors.forename: Luiz Ricardo
authors.initials: LR
authors.lastname: Goulart
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)|Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
authors.forename: Patrícia Terra
authors.initials: PT
authors.lastname: Alves
authors.affiliation: Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
authors.forename: Bellisa de Freitas
authors.initials: Bde F
authors.lastname: Barbosa
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)|Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, Mato Grosso, Brazil (WRL)
authors.forename: Wânia Rezende
authors.initials: WR
authors.lastname: Lima
authors.affiliation: Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
authors.forename: Neide Maria
authors.initials: NM
authors.lastname: Silva
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure; D018938:Caco-2 Cells; D016764:Cell Polarity; D062445:Claudin-1 / Q000378:metabolism; D003911:Dextrans / Q000378:metabolism; D017097:Electric Impedance; D004705:Endocytosis; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000469:parasitology* / Q000648:ultrastructure; D008871:Microvilli / Q000378:metabolism / Q000469:parasitology / Q000648:ultrastructure; D062793:Occludin / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism / Q000469:parasitology / Q000648:ultrastructure; D014122:Toxoplasma / Q000502:physiology*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D062445:Claudin-1; D003911:Dextrans; D062793:Occludin; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein
keywords: Caco-2 cells; Toxoplasma gondii; epithelial barrier dysfunction; tight junctions