posted on 2023-01-02, 23:04authored byYilan Liu, Jinjin Chen, Kaushik Raj, Lauren Baerg, Nayanan Nathan, Dana J. Philpott, Radhakrishnan Mahadevan
Both Gram-positive and Gram-negative bacteria release
nanosized
extracellular vesicles called membrane vesicles (MVs, 20–400
nm), which have great potential in various biomedical applications
due to their abilities to deliver effector molecules and induce therapeutic
responses. To fully utilize bacterial MVs for therapeutic purposes,
regulated and enhanced production of MVs would be highly advantageous.
In this study, we developed a universal method to enhance MV yields
in both G+/G– bacteria through an autonomous controlled peptidoglycan
hydrolase (PGase) expression system. A significant increase (9.37-fold)
of MV concentration was observed in engineered E. coli Nissle 1917 compared to the wild-type. With the help of this autonomous
system, for the first time we experimentally confirmed horizontal
gene transfer and nutrient acquisition in a cocultured bacterial consortium.
Furthermore, the engineered probiotic E. coli strains with high yield of MVs showed higher activation of the innate
immune responses in human embryonic kidney 293T (HEK293T) and human
colorectal carcinoma cells (HCT116), thereby demonstrating the great
potential of engineering probiotics in immunology and further living
therapeutics in humans.