Publicação
The impact of LPS induced tolerance on macrophage-bacterial interaction
| Resumo: | The innate immune system constitutes one of the first lines of defence against pathogens and plays a crucial role in shaping host-pathogen interactions. Lipopolysaccharide (LPS) is a Pathogen-Associated Molecular Pattern (PAMP) that can either trigger immune cell activation or induce tolerance, depending on dosage and stimulation conditions. The host microbiota can also shape, and be shaped by, innate immune responses. Dysbiosis, commonly associated with aging and inflammatory bowel diseases, can increase gut permeability, thereby facilitating the translocation of bacterial products such as LPS into the bloodstream. Repeated or prolonged exposure to LPS may induce endotoxin tolerance, which in turn can influence the evolution and composition of the gut microbiota. However, the precise role of LPS-induced immune tolerance in bacterial evolution remains largely unexplored. To address this subject, we established both in vitro and in vivo models of tolerance by repeated stimulation with low doses of LPS. The in vitro model used THP-1 macrophages exposed to LPS and aimed to establish an LPS tolerance model. It further aimed at determining how Escherichia coli (E. coli) survives in co-culture with LPS tolerant macrophages. The in vivo model consisted of mice intraperitoneally injected with LPS, from which macrophages were isolated, and aimed to describe how in vivo LPS exposure impacts response to ex vivo LPS stimulation. We established a model with early signs of tolerance with THP-1 derived macrophages repeatedly exposed to LPS but did not see differences in E. coli viability when grown with these macrophages compared to non-tolerant macrophages. Peritoneal macrophages and bone marrow derived macrophages from mice exposed to LPS in vivo both showed a modulated response when stimulated ex vivo. Peritoneal macrophages showed signs of tolerance, whereas bone marrow derived ones showed signs of immune priming. Future work should aim to solidify the LPS tolerance model with THP-1 derived macrophages, explore cytokine secretion by tolerant macrophages exposed to E. coli co-culture, co-culture macrophages and E. coli across longer periods (15 to 30 days) and culture cells derived from LPS exposed mice with E. coli to observe bacterial adaptation. |
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| Autores principais: | Batista, Guilherme Jose Cardoso |
| Assunto: | Macrophages Lipopolysaccharide Lipopolysaccharide tolerance Innate immunity Escherichia coli |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | The innate immune system constitutes one of the first lines of defence against pathogens and plays a crucial role in shaping host-pathogen interactions. Lipopolysaccharide (LPS) is a Pathogen-Associated Molecular Pattern (PAMP) that can either trigger immune cell activation or induce tolerance, depending on dosage and stimulation conditions. The host microbiota can also shape, and be shaped by, innate immune responses. Dysbiosis, commonly associated with aging and inflammatory bowel diseases, can increase gut permeability, thereby facilitating the translocation of bacterial products such as LPS into the bloodstream. Repeated or prolonged exposure to LPS may induce endotoxin tolerance, which in turn can influence the evolution and composition of the gut microbiota. However, the precise role of LPS-induced immune tolerance in bacterial evolution remains largely unexplored. To address this subject, we established both in vitro and in vivo models of tolerance by repeated stimulation with low doses of LPS. The in vitro model used THP-1 macrophages exposed to LPS and aimed to establish an LPS tolerance model. It further aimed at determining how Escherichia coli (E. coli) survives in co-culture with LPS tolerant macrophages. The in vivo model consisted of mice intraperitoneally injected with LPS, from which macrophages were isolated, and aimed to describe how in vivo LPS exposure impacts response to ex vivo LPS stimulation. We established a model with early signs of tolerance with THP-1 derived macrophages repeatedly exposed to LPS but did not see differences in E. coli viability when grown with these macrophages compared to non-tolerant macrophages. Peritoneal macrophages and bone marrow derived macrophages from mice exposed to LPS in vivo both showed a modulated response when stimulated ex vivo. Peritoneal macrophages showed signs of tolerance, whereas bone marrow derived ones showed signs of immune priming. Future work should aim to solidify the LPS tolerance model with THP-1 derived macrophages, explore cytokine secretion by tolerant macrophages exposed to E. coli co-culture, co-culture macrophages and E. coli across longer periods (15 to 30 days) and culture cells derived from LPS exposed mice with E. coli to observe bacterial adaptation. |
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