Optimizing of Culture Conditions for the Isolation and Characterization of Extracellular Vesicles Derived from Lactobacillus crispatus PMC201

Extracellular vesicles (EVs) carry diverse cargo of DNA, RNA, proteins, and lipids. They are crucial mediators for regulating various functions through interactions with the host. Recent investigations suggest that EVs or their constituent proteins derived from probiotics could improve the effectiveness of probiotic strains in disease management compared to probiotic strains themselves. This enhanced effec-tiveness arises from their innate antimicrobial properties, which can specifically target pathogenic mol-ecules or cells, in addition to their significant ability to regulate immune responses. Significantly, previous studies have highlighted the inhibitory potential of Lactobacillus crispatus PMC201 against Mycobacterium tuberculosis. In this study, we focused on optimizing isolation conditions for studying extracellular vesicles and proteins from anti-TB potent strains. We provide analysis results based on food-grade media (FGM) optimization and isolation methods. Nanoparticle tracking analysis (NTA) was used to determine se-cretion patterns. Proteomic analysis was performed by liquid chromatography and tandem mass spec-trometry (LC-MS/MS). A total of 64 proteins were identified in the L. crispatus PMC201 strain, particularly enriched in s-layer and splX. Questions remain about their relevance to anti-TB. This anti-tuber strain has potential as a therapeutic agent, given its significant role in intercellular killing. Further studies are needed to investigate its mechanisms of action.