Regarding the important role of A. muciniphila in gut barrier integrity and decreasing permeability which prevents metabolic disorders associated with obesity54,55, the present study showed that MOI 10 of A. muciniphila and both concentrations of 50 and 100 μg/mL of A. muciniphila-derived OMVs could decrease the level of CB1 mRNA in Caco-2 cells which promotes the idea of using the active A. muciniphila as a probiotic candidate and bacterial-derived OMVs for CB1 expression regulation to prevent metabolic disorders associated with obesity. Here, CNR1 is linked to obesity due to melanocortin 4 receptor deficiency.