Fusobacterium nucleatum-derived extracellular vesicles carrying virulence factor DNA trigger AIM2 inflammasome activation to facilitate UC progression Original paper
Researched by:
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Divine Aleru
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Divine Aleru
Read MoreI am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
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Microbes
Microbes
Microbes are microscopic organisms living in and on the human body, shaping health through digestion, vitamin production, and immune protection. When microbial balance is disrupted, disease can occur. This guide explains key microbe types—bacteria, viruses, fungi, protozoa, and archaea—plus major pathogenic and beneficial examples.
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Divine Aleru
Read More
Researched by:
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Divine Aleru
ID
Divine Aleru
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was studied?
This study focused on the role of Fusobacterium nucleatum extracellular vesicles (Fn-EVs) in triggering the AIM2 inflammasome and its role in facilitating the progression of ulcerative colitis (UC). The research specifically examined how Fn-EVs, containing DNA from F. nucleatum, are internalized by intestinal epithelial cells (IECs), activating the AIM2 inflammasome and leading to pyroptosis, which disrupts the intestinal barrier and exacerbates UC.
Who was studied?
The study involved clinical samples from patients diagnosed with active UC and mouse models of experimental colitis induced by dextran sulfate sodium (DSS). The study utilized human biopsies and peripheral blood samples from 20 UC patients, comparing them with healthy controls. In vitro, human intestinal epithelial cell lines (NCM460) were treated with Fn-EVs to observe their impact on the AIM2 inflammasome and pyroptosis. In vivo experiments used C57BL/6 mice treated with F. nucleatum and DSS to investigate the role of Fn-EVs in UC progression.
What were the most important findings?
The study identified that Fusobacterium nucleatum-derived extracellular vesicles (Fn-EVs) contain virulence factor DNA, which triggers activation of the AIM2 inflammasome in intestinal epithelial cells (IECs). This process leads to pyroptosis and disruption of the intestinal barrier, key features of UC progression. Bioinformatics analysis showed that AIM2 expression and related genes were significantly upregulated in active UC samples, correlating with bacterial invasion and tight junction damage. In vitro, the internalization of Fn-EVs by IECs activated the AIM2 inflammasome, leading to increased expression of pyroptosis-related markers such as GSDMD, IL-1β, and IL-18. This activation was linked to the breakdown of tight junction proteins (ZO-1 and occludin), which are essential for maintaining the integrity of the intestinal barrier. In vivo, treatment with A151, an AIM2 inflammasome inhibitor, alleviated disease symptoms, such as weight loss and histological damage, in DSS-induced colitis mice, providing therapeutic evidence that targeting the AIM2 pathway could mitigate UC progression.
What are the greatest implications of this study?
The findings of this study reveal that Fusobacterium nucleatum and its extracellular vesicles contribute significantly to UC progression by activating the AIM2 inflammasome in intestinal epithelial cells. These results suggest that Fn-EVs can act as vehicles for pathogenic DNA, which triggers inflammation and epithelial cell death, exacerbating UC. This study opens new avenues for therapeutic intervention, particularly in targeting the AIM2 inflammasome pathway. By inhibiting the Fn-EVs-DNA-AIM2 cascade with agents like A151 or DNase I, it may be possible to restore gut barrier integrity and reduce inflammation, offering potential for novel therapeutic strategies in UC treatment. Moreover, the findings highlight the importance of monitoring Fn-EVs in UC diagnosis and management, suggesting a potential biomarker for disease severity and progression.
Fusobacterium nucleatum
Fusobacterium nucleatum is a Gram-negative, anaerobic bacterium commonly found in the oral cavity, where it plays a crucial role in the formation of biofilms. Beyond its presence in the mouth, Fn is implicated in a variety of systemic conditions, including periodontal disease, colorectal cancer, and inflammatory bowel disease. Known for its ability to coaggregate with other bacteria, Fn's pathogenic potential is magnified in dysbiotic microbial communities, making it a key player in polymicrobial infections. The bacterium utilizes multiple virulence factors such as FadA and Fap2, which facilitate adhesion to host tissues and immune evasion, ultimately contributing to its role in chronic and inflammatory diseases.