Gut microbiota-derived extracellular vesicles isolated from patients with chronic granulomatous disease

Chronic granulomatous disease (CGD) is caused by nicotinamide adenine dinucleotide phosphate oxidase complex 2 (NOX2) mutations leading to defective phagocyte-derived reactive oxygen species (ROS) production. Individuals with CGD have increased inflammasome activation in circulating phagocytes and 50% of patients will develop inflammatory bowel disease (CGD-IBD) associated with a distinct intestinal microbiome signature. The mechanisms by which intestinal dysbiosis in CGD-IBD impact inflammation are unknown. Bacteria produce extracellular vesicles carrying cargo that can have immunomodulatory effects. Gut microbiota-derived extracellular vesicles (GMEVs), can impact the intestinal barrier and translocate into systemic circulation, thereby interacting with immune cells. Here, we evaluated the microbiota differences in CGD individuals with or without Intestinal Bowel Disease (IBD). Further, the impact of GMEVs were evaluated by assessing intestinal barrier permeability, and inflammatory responses in intestinal organoids and THP1-derived macrophages (wild type and CGD) exposed to GMEVs from CGD individuals with IBD as compared to those without IBD. The results show distinct microbiome changes between the CGD-No IBD group and CGD-IBD group. CGD-IBD GMEVs increased intestinal barrier inflammation and permeability compared to GMEVs from patients with CGD without IBD. CGD-IBD GMEVs significantly increased pro-inflammatory responses, including inflammasome activation and visualization in wild type and CGD THP1-derived macrophages. Interactions between CGD-IBD GMEVs and host cells leading to pro-inflammatory responses were dependent on TLR4 activation and not endocytosis of the GMEVs. Our results strongly suggest that GMEVs isolated from individuals with CGD-IBD may be important contributors to the underlying pro-inflammatory phenotype of patients with CGD-IBD, including playing a role in increased inflammasome activation.