Session: Parallel session 5 - Forensic and cultural heritage
Characterization by multi-Omics of the virulence potential of Bacillus thuringiensis subspecies using an in vitro intestinal epithelial model
Introduction
Bacillus thuringiensis (Bt) are widely used biopesticides, due to production of insecticidal proteins. As part of the Bacillus cereus group, Bt possesses and share virulence genes encoding pore-forming enterotoxins involved in FBOs. Given extensive agricultural Bt biopesticides application and probable increase of human exposure through food, their virulence potential to human health should be further investigated. This study aimed to elucidate which molecular mechanisms are induced in a human intestinal cell model after Bt treatment using multi-omics.
Methodology
Differentiated Caco-2 cells were exposed for 24 hours to bacterial supernatants from different Bt strains and to a B. cytotoxicus (Bcyt) supernatant isolated from FBOs. First, cytotoxicity (MTT) and pro-inflammatory (IL-8 release) assays were carried out. Then, 3 non-cytotoxic concentrations of Bt and Bcyt supernatants were selected to investigate the impact on the extra and intracellular proteome and metabolome, using Q-Exactive Plus coupled to a UHPLC system.
Results & Discussion
Unlike Bcyt, Bt supernatants did not induce cytotoxicity on Caco-2 cells, but increased IL-8 release. Both of Bt and Bcyt supernatants induced similar effects on Caco-2 cells as: (i) increased transporter abundances, probably to compensate metabolite leakage due to toxin-created pores, (ii) disrupted histone abundances and (iii) adapted energy metabolism. Unlike Bcyt, Bt supernatants increased also abundances of complement system inhibitors, like CD59, suggesting intestinal cell protection response involving defense mechanisms. Differences in the toxin profile of the various Bt subspecies were also observed. These results highlight that Bt biopesticides may provoke long-term effects due to inflammation and impact on cellular metabolism. Further work is needed to link the toxic effects reported and the specific toxin profiles characteristic of each Bt subspecies.
Bacillus thuringiensis (Bt) are widely used biopesticides, due to production of insecticidal proteins. As part of the Bacillus cereus group, Bt possesses and share virulence genes encoding pore-forming enterotoxins involved in FBOs. Given extensive agricultural Bt biopesticides application and probable increase of human exposure through food, their virulence potential to human health should be further investigated. This study aimed to elucidate which molecular mechanisms are induced in a human intestinal cell model after Bt treatment using multi-omics.
Methodology
Differentiated Caco-2 cells were exposed for 24 hours to bacterial supernatants from different Bt strains and to a B. cytotoxicus (Bcyt) supernatant isolated from FBOs. First, cytotoxicity (MTT) and pro-inflammatory (IL-8 release) assays were carried out. Then, 3 non-cytotoxic concentrations of Bt and Bcyt supernatants were selected to investigate the impact on the extra and intracellular proteome and metabolome, using Q-Exactive Plus coupled to a UHPLC system.
Results & Discussion
Unlike Bcyt, Bt supernatants did not induce cytotoxicity on Caco-2 cells, but increased IL-8 release. Both of Bt and Bcyt supernatants induced similar effects on Caco-2 cells as: (i) increased transporter abundances, probably to compensate metabolite leakage due to toxin-created pores, (ii) disrupted histone abundances and (iii) adapted energy metabolism. Unlike Bcyt, Bt supernatants increased also abundances of complement system inhibitors, like CD59, suggesting intestinal cell protection response involving defense mechanisms. Differences in the toxin profile of the various Bt subspecies were also observed. These results highlight that Bt biopesticides may provoke long-term effects due to inflammation and impact on cellular metabolism. Further work is needed to link the toxic effects reported and the specific toxin profiles characteristic of each Bt subspecies.