Outer Membrane Vesicles Have Role in Microbe-Host Communication

An international research team led by scientists from the Neuroscience Centre of Goethe University has shared insights as to how bacteria distribute their metabolic products. Their findings were published in Journal of Extracellular Vesicles.

The researchers colonized the intestines of mice with E. coli bacteria, which produced a specific type of gene scissors, called Cre, and released these into their environment via vesicles. The mice cells contained a gene for a red fluorescent protein, which could be activated by the Cre gene scissors (Cre/LoxP system). In the subsequent examination of the mouse tissue, the bacterial vesicles had been absorbed by individual cells in the intestine, liver, spleen, heart, and kidneys as well as by immune cells. Consequently, functional Cre contained in the vesicles could enter the cells and lead to the expression of the red marker protein. Even individual nerve cells in the brain glowed red.

Researcher Stefan Momma says, “[We find it] particularly impressive is the fact that the bacteria’s vesicles can also overcome the blood-brain barrier and in this way enter the brain—which is otherwise more or less hermetically sealed. And that the bioactive bacterial substances were absorbed by stem cells in the intestinal mucosa shows us that intestinal bacteria can possibly even permanently change its properties.”

The fluorescence images indicate, says Momma, that the vesicles were probably distributed throughout the body via the bloodstream. “The further study of these communication pathways from the bacterial kingdom to individual mammalian cells will not only improve our understanding of conditions such as autoimmune diseases or cancer, in which the microbiome quite obviously plays a significant role. Such vesicles are also extremely interesting as a new method to deliver drugs or develop vaccines, or as biomarkers that point to a pathological change in the microbiome.”