The effect of Lactobacillus casei derived extracellular vesicles on the expression of Toll-like receptor-2 gene

In Gram-positive bacteria, the production of extracellular vesicles has been neglected to date due to the presence of a thick peptidoglycan cell wall. But in recent years more studies have been done on these nanoparticles. The purpose of this study is to show that Lactobacillus casei has the ability to produce extracellular vesicles. Since extracellular vesicles (EVs) are an important agent to mediate the expression of genes. In this scientific research, we have examined to find out the effect of EVs derived from L. casei on the expression of Toll-like receptor 2 gene. The EVs were purified from the conditioned medium of L. casei using ultracentrifugation and confirmed by scanning electron microscopy (SEM). The Caco2 cells were treated with different concentrations of purified extracellular vesicles. The electron microscopy showed spherical vesicles that had an average diameter of 200nm. The extracted protein content was 2.4 in the ultracentrifugation method. It was determined that the extracellular vesicles of this bacterium at concentrations of 150 μg/ml had no significant effect on the expression of Toll-like receptor-2 gene expression in comparison with the control (Sucrose), whereas the expression of this gene in the treatment of EVs at concentrations of 50 and 100 μg/ml decreased. Our result creates a paradigm for future studies of the functional component from gut microbiota as a new possible dietary supplement instead of probiotic.