Examinando por Autor "Schinnerling, Katina"
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Ítem Efecto de Prevotella copri sobre la viabilidad, activación y diferenciación de monocitos y macrófagos(Universidad Andrés Bello, 2023) Muñoz Mora, Karim Fernanda; Schinnerling, Katina; Facultad de Ciencias de la VidaLa microbiota intestinal es una comunidad de diversos géneros bacterianos comensales que interactúan con el individuo en el que habitan, causando impacto en el sistema inmune. Sin embargo, su disbiosis se asocia con el desarrollo de patologías inflamatorias como la Artritis Reumatoide (AR), enfermedad autoinmune que causa la degradación de cartílago y material óseo en las articulaciones sinoviales. Varios estudios han relacionado la AR a la especie Prevotella copri (P. copri) encontrándose sobreabundante en la microbiota intestinal de pacientes con AR temprana y pre-clínica. Se ha demostrado que P. copri promueve el desarrollo de artritis experimental en ratones SKG e induce un aumento de linfocitos Th17. Además, P. copri reduce el grosor de la capa protectora de la mucosa intestinal. Esto sugiere la participación de P. copri en el desarrollo y progresión de AR. Para dilucidar el mecanismo por el cual P. copri podría contribuir a la inmunopatogénesis de la AR, este proyecto se enfoca en investigar los efectos de P. copri sobre monocitos y macrófagos humanos. Dado que se ha reportado que pacientes con AR activa presentan un sesgo hacia macrófagos proinflamatorios M1, se hipotetiza que P. copri reduce la viabilidad, promueve la activación y diferenciación de monocitos y macrófagos hacia un perfil M1 in vitro. El objetivo general es evaluar el efecto de P. copri sobre la viabilidad, activación y diferenciación de monocitos y macrófagos in vitro. Como modelo de monocitos se empleó la línea celular THP1, que puede diferenciarse a macrófagos al ser expuesta a PMA. Se determinó el efecto de P. copri sobre la viabilidad de monocitos y macrófagos in vitro, mediante marcaje con Anexina V y una sonda de viabilidad mediante citometría de flujo. Luego, se evaluó el efecto de P. copri sobre la activación y diferenciación de monocitos y macrófagos in vitro, mediante el análisis de marcadores para M1/M2 y del perfil de citoquinas por citometría de flujo. Este estudio contribuye al conocimiento sobre la interacción entre P. copri y el sistema inmune innato, particularmente los monocitos y macrófagos, en la inmunopatogénesis de AR, que podrían asociarse al desarrollo y propagación de inflamación crónica en AR.Ítem Human metapneumovirus respiratory infection affects both innate and adaptive intestinal immunity(Frontiers Media SA, 2024) Sepúlveda-Alfaro, Javiera; Catalán, Eduardo A.; Vallejos, Omar P.; Ramos-Tapia, Ignacio; Madrid-Muñoz, Cristóbal; Mendoza-León, María J.; Suazo, Isidora D.; Rivera-Asin, Elizabeth; Silva, Pedro H.; Alvarez-Mardones, Oscar; Castillo-Godoy, Daniela P.; Riedel, Claudia A.; Schinnerling, Katina; Ugalde, Juan A.; Soto, Jorge A.; Bueno, Susan M.; Kalergis, Alexis M.; Melo-Gonzalez, FelipeIntroduction: Respiratory infections are one of the leading causes of morbidity and mortality worldwide, mainly in children, immunocompromised people, and the elderly. Several respiratory viruses can induce intestinal inflammation and alterations in intestinal microbiota composition. Human metapneumovirus (HMPV) is one of the major respiratory viruses contributing to infant mortality in children under 5 years of age worldwide, and the effect of this infection at the gut level has not been studied. Methods: Here, we evaluated the distal effects of HMPV infection on intestinal microbiota and inflammation in a murine model, analyzing several post-infection times (days 1, 3, and 5). Six to eight-week-old C57BL/6 mice were infected intranasally with HMPV, and mice inoculated with a non-infectious supernatant (Mock) were used as a control group. Results: We did not detect HMPV viral load in the intestine, but we observed significant changes in the transcription of IFN-γ in the colon, analyzed by qPCR, at day 1 post-infection as compared to the control group. Furthermore, we analyzed the frequencies of different innate and adaptive immune cells in the colonic lamina propria, using flow cytometry. The frequency of monocyte populations was altered in the colon of HMPV -infected mice at days 1 and 3, with no significant difference from control mice at day 5 post-infection. Moreover, colonic CD8+ T cells and memory precursor effector CD8+ T cells were significantly increased in HMPV-infected mice at day 5, suggesting that HMPV may also alter intestinal adaptive immunity. Additionally, we did not find alterations in antimicrobial peptide expression, the frequency of colonic IgA+ plasma cells, and levels of fecal IgA. Some minor alterations in the fecal microbiota composition of HMPV -infected mice were detected using 16s rRNA sequencing. However, no significant differences were found in β-diversity and relative abundance at the genus level. Discussion: To our knowledge, this is the first report describing the alterations in intestinal immunity following respiratory infection with HMPV infection. These effects do not seem to be mediated by direct viral infection in the intestinal tract. Our results indicate that HMPV can affect colonic innate and adaptive immunity but does not significantly alter the microbiota composition, and further research is required to understand the mechanisms inducing these distal effects in the intestine.Ítem Intestinal barrier dysfunction mediates Whipple's disease immune reconstitution inflammatory syndrome (IRIS)(John Wiley and Sons Inc, 2022-05) Friebel, Julian; Schinnerling, Katina; Geelhaar-Karsch, Anika; Allers, Kristina; Schneider, Thomas; Moos, VerenaBackground & Aims: Classical Whipple's disease (CWD) affects the gastrointestinal tract and causes chronic diarrhea, malabsorption, and barrier dysfunction with microbial translocation (MT). Immune reconstitution inflammatory syndrome (IRIS) is a serious complication during antimicrobial treatment of CWD. The pathomechanisms of IRIS have not been identified and mucosal barrier integrity has not been studied in patients with IRIS CWD. Methods: In 96 CWD patients (n = 23 IRIS, n = 73 non-IRIS) and 30 control subjects, we analysed duodenal morphology by histology, measured serum markers of MT, and proinflammatory cytokines in biopsy supernatants, and correlated microbial translocation with T cell reconstitution and activation. Results: Before treatment, duodenal specimens from patients who later developed IRIS exhibited a more pronounced morphological transformation that suggested a disturbed barrier integrity when compared with the non-IRIS group. Villous atrophy was mediated by increased apoptosis of epithelial cells, which was insufficiently counterbalanced by regenerative proliferation of crypt cells. Pretreatment deficiencies in the mucosal secretion of proinflammatory cytokines and chemokines (e.g., IL-6, CCL2) in these patients markedly resolved after therapy induction. High serum levels of lipopolysaccharides (LPS), soluble CD14 (sCD14), and LPS-binding protein (LBP) combined with low endotoxin core antibody (EndoCAb) titres suggested systemic MT in CWD patients developing IRIS. CD4+ T cell count and activation in IRIS CWD patients correlated positively with sCD14 levels and negatively with EndoCAb titres. Furthermore, the degree of intestinal barrier dysfunction and MT was predictive for the onset of IRIS. Conclusion: Prolonged MT across a dysfunctional intestinal mucosal barrier due to severe tissue damage favors dysbalanced immune reconstitution and systemic immune activation in IRIS CWD. Therefore, the monitoring of inflammatory and MT markers in CWD patients might be helpful in identifying patients who are at risk of developing IRIS. Therapeutic strategies to reconstitute the mucosal barrier and control inflammation could assist in the prevention of IRIS. © 2022 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.Ítem Uptake of Tropheryma whipplei by Intestinal Epithelia(MDPI, 2023-04) Friebel, Julián; Schinnerling, Katina; Weigt, Kathleen; Heldt, Claudia; Fromm, Anja; Bojarski, Christian; Siegmund, Britta; Epple, Hans-Jörg; Kikhney, Judith; Moter, Annette; Schneider, Thomas; Schulzke, Jörg D.Background: Tropheryma whipplei (TW) can cause different pathologies, e.g., Whipple’s disease and transient gastroenteritis. The mechanism by which the bacteria pass the intestinal epithelial barrier, and the mechanism of TW-induced gastroenteritis are currently unknown. Methods: Using ex vivo disease models comprising human duodenal mucosa exposed to TW in Ussing chambers, various intestinal epithelial cell (IEC) cultures exposed to TW and a macrophage/IEC coculture model served to characterize endocytic uptake mechanisms and barrier function. Results: TW exposed ex vivo to human small intestinal mucosae is capable of autonomously entering IECs, thereby invading the mucosa. Using dominant-negative mutants, TW uptake was shown to be dynamin- and caveolin-dependent but independent of clathrin-mediated endocytosis. Complementary inhibitor experiments suggested a role for the activation of the Ras/Rac1 pathway and actin polymerization. TW-invaded IECs underwent apoptosis, thereby causing an epithelial barrier defect, and were subsequently subject to phagocytosis by macrophages. Conclusions: TW enters epithelia via an actin-, dynamin-, caveolin-, and Ras-Rac1-dependent endocytosis mechanism and consecutively causes IEC apoptosis primarily in IECs invaded by multiple TW bacteria. This results in a barrier leak. Moreover, we propose that TW-packed IECs can be subject to phagocytic uptake by macrophages, thereby opening a potential entry point of TW into intestinal macrophages.