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  • Interactions of bacteroides dorei with intestinal epithilial cells
    Publication . Matos, Isabel Cristina Soares Curado de; Faleiro, Leonor
    Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of pancreatic beta cells, leading to insufficient insulin production. Intestinal dysbiosis, (unbalanced microbiota composition), has been associated with T1D. High population levels of bacteria belonging to the phylum Bacteroidetes have been reported in children with T1D, in contrast to healthy children. The intestinal metaproteome of children with T1D from the Algarve region has shown to be enriched with proteins originating from Bacteroides spp., including B. dorei and B. uniformis. Faecal analyzes allowed the isolation of these species from T1D and Control children of Algarve. The main goal of the current study was to evaluate the interactions between Bacteroides spp. isolates, including B. dorei, and the intestinal epithelial cells HT29-MTX-E12. All tested Bacteroides spp. were able to adhere to HT-29-MTX-E12 cells, ranging from 75.43 ± 2.98% to 83.06 ± 1.29%. B. dorei strains were able to invade HT-29-MTX-E12 ranging from 70.11 ± 5.66% to 85.25 ± 5.42%. In contrast, the strains of B. uniformis were not able to invade. Parabacteroides distasonis PtF D14MH1 showed the highest invasion ability (97.38 ± 1.62%). Disruption of the tight junctions of HT29-MTX-E12 cells was evident after exposure to B. dorei and P. distasonis isolates in contrast to slightly impaired after exposure to B. uniformis isolates. The viability of HT29-MTX-E12 cells decreased after exposure to the bacterial supernatant, and it was most evident when the medium was supplemented with 25 and 50% (v/v) of bacterial supernatant. The invasive ability of Bacteroides spp. significantly decreases in the presence of Lactobacillus casei DSM 20011. Cytokine production by HT29-MTX-E12 cells exposed to Bacteroides spp. was not noticeable and only induced the production of IL-8 and MIP-1β. The damage caused by Bacteroides spp. to the intestinal epithelial cells (disruption of cell junctions, decreased cell viability, adherence and invasive ability of the isolates) may contribute to dysbiosis in children with T1D.
    2019-11-12Dissertação de mestrado Acesso aberto Ver mais