An engineered bacterium for the targeted delivery of proteins to destroy Pseudomonas aeruginosa biofilms

Abstract:

[Objective] With the development of synthetic biology, great progress has been made in targeted therapy by designing and synthesizing complex, multifunctional gene circuits in bacteria. Although using bacteria as a therapeutic delivery system to selectively release effective therapeutic components in vivo has great advantages, how to make bacteria secrete functional proteins effectively and play a role under low metabolic load remains a challenge.[Methods] To solve this problem, this study provided a new strategy. In this strategy, protein germicide and filamentous phage encoding genes widely existed in bacteria were used as biobricks, and through the rearrangement and assembly of these endogenous biobricks of P. aeruginosa, an engineered bacterium capable of lysis and release of functional proteins under specific conditions was constructed. In order to evaluate whether the biobricks constructed in the engineered bacterium could work, the extracellular polysaccharides hydrolase PelA and PslG were selected as functional proteins to construct the engineered bacterium PAO1102. The destruction and prevention effects of PAO1102 on P. aeruginosa biofilm were tested by the biofilm destruction experiment, biofilm inhibition experiment and antibiotic resistance experiment.[Results] Compared with the control group, the treatment of PAO1102 could not only significantly destroy the mature biofilm and inhibit the biofilm formation, but also significantly enhance the sensitivity of the bacteria in the biofilm to tobramycin. Moreover, these functions of PAO1102 were mainly dependent on the release of functional proteins by phage Pf4 induced cell lysis.[Conclusion] The engineered bacterium could be used as a microbial tool for the targeted delivery of proteins. In the follow-up study, different functional genes will be expressed in the engineered bacterium according to different needs, and the targeted delivery of functional proteins will be realized, to perform different biological functions.