Solomon, T. J. | Search bioRxiv

bioRxiv2025

Human cell-derived extracellular vesicles exhibit anti-biofilm effects against Pseudomonas aeruginosa

The need for new antimicrobial approaches is one of the most pressing issues in modern medicine. A particular pathogen of concern is multidrug resistant Pseudomonas aeruginosa, which is implicated in over 1 million deaths worldwide yearly. One potential class of novel antimicrobials is extracellular vesicles (EVs), which have been found to have intrinsic antimicrobial and anti-virulence properties. Here, the antimicrobial activity of EVs on P. aeruginosa was explored in the context of biofilms of hyper-virulent strain PA14. We identified the human monocyte cell line THP-1 as a promising source of EVs for this application, inducing reduced PA14 biofilm formation in a dose-dependent manner. THP-1 EVs were not found to affect P. aeruginosa growth planktonically within the biofilm assay or in shaken culture. Additionally, we demonstrate that anti-biofilm effects were conserved with similar efficacy across THP-1 monocyte and differentiated THP-1 macrophage-derived EVs. Further, EVs from induced pluripotent stem cell-derived mesenchymal stem/stromal cells (iMSCs) also reduced PA14 biofilm formation to a similar extent as THP-1 EVs, while EVs from human embryonic kidney cells (HEK293T) had a similar effect to its media control. This work indicates that human cell-derived EVs from several sources possess biological and/or physical properties that reduce PA14 biofilm formation.

microbiology↗

bioRxiv2025

Genetically-programmed Hypervesiculation of Lactiplantibacillus plantarum Increases Production of Bacterial Extracellular Vesicles with Therapeutic Efficacy in a Preclinical Inflammatory Bowel Disease Model

Inflammatory bowel diseases (IBD) affect over 6 million people globally and current treatments achieve only 10-20% rates of durable disease remission. Bacterial extracellular vesicles (BEVs) from probiotic lactic acid bacteria (LAB) are a promising novel therapeutic with mechanisms holding potential to drive increased rates of durable disease remission, including immunomodulation and intestinal epithelial tissue repair. However, translation of these cell-secreted nanovesicles is limited by long standing biomanufacturing hurdles, especially low production yields due to low biogenesis rates from cells. Here, our goal was to identify a candidate probiotic LAB that produces BEVs effective in a preclinical mouse model of IBD, and then genetically engineer the LAB for at least 10-fold increased production yields of BEVs, thereby passing a critical production threshold. We identified Lactiplantibacillus plantarum as a candidate LAB producing BEVs effective in treating acute dextran sulfate sodium (DSS)-induced murine colitis, and with greater efficacy than BEVs from probiotic Escherichia coli Nissle 1917. We then genetically engineered a hypervesiculating L. plantarum strain by inducible expression of a peptidoglycan-modifying enzyme, resulting in a 66-fold increase in BEV productivity. Finally, we confirmed hypervesiculating L. plantarum BEVs were therapeutically effective in the acute DSS mouse model of colitis and found these BEVs were superior in reducing mucosal tissue damage compared to live L. plantarum cells. These findings demonstrate that BEVs from genetically engineered hypervesiculating strain of L. plantarum are a promising preclinical therapeutic candidate for IBD that overcomes historical biomanufacturing limitations of BEV therapeutics.

bioengineering↗