Bacterial Extracellular Vesicles (BEVs) Derived From Lactococcus lactis as Multimodal Drug Delivery Platforms.

Advances in drug delivery technologies involve the extracellular vesicles as a promising bioactive drug delivery vehicle expected to improve targeted therapeutic delivery in pharmaceutical innovations. Recently, Gram-negative bacterial extracellular vesicles (outer membrane vesicles or OMVs) have gained attention for their role in host-microbe interactions and potential in drug delivery. Bacterial extracellular vesicle (BEV) shedding is a conserved mechanism of intra- and interspecies communication, providing critical insights into host-microbe interactions. However, the biogenesis and compositional diversity of BEVs produced by Gram-positive bacteria remain underexplored. Understanding the translational application potential of BEVs remains elusive due to the suboptimal isolation of BEVs and limited structural-functional characterization. A comprehensive study to develop BEVs as delivery vehicles will provide critical insights into the perspective of microbial-host interplay and illuminate the modulation of the drug delivery strategy. Here, using a food-grade probiotic Lactococcus lactis subsp. cremoris MG1363 (strain NZ9000), we demonstrated that perturbing peptidoglycan biosynthesis with ampicillin, which targets penicillin-binding proteins (PBPs), significantly enhances BEV production. We further explored the interaction between BEVs and host cells through this optimized BEV biogenesis, revealing its cargo-delivering capability. Furthermore, to understand the potential of BEVs as a multimodal drug delivery platform, we target multidrug-resistant microbial pathogens and cancer cell proliferation with drug-encapsulated BEVs. With a generally recognized as safe (GRAS) recognition of L. lactis, we demonstrated that drug-loaded L. lactis BEVs can offer recognizable therapeutic effects. These findings highlight the versatile nature of L. lactis BEVs as stable, safe, natural nanocarriers capable of personalized cargo delivery with broad therapeutic applications.