Event

Title: Defining Bacterial Extracellular Vesicle Interactions with Target Cells: Implications for Wound Repair and Gut-Brain Axis Communication

Committee Members:
Dr. Steven M. Jay, Chair
Dr. Sara Molinari
Dr. Erika Moore

Abstract:

This study evaluates the biological effects of probiotic bacterial extracellular vesicles across two systems, wound healing and neuropod-like enteroendocrine signaling. Bacterial extracellular vesicles are nanoscale particles that carry bioactive cargo and mediate communication between microbes and host cells. In the wound healing context, their effects on endothelial migration, angiogenesis, and inflammation were assessed using scratch assays, tube formation assays, and macrophage cytokine analysis. Probiotic vesicles promoted endothelial migration and angiogenesis in a strain- and dose-dependent manner, with Lactiplantibacillus plantarum showing strong effects on migration and Bifidobacterium enhancing angiogenic responses. Inflammatory signaling was reduced at higher vesicle concentrations, indicating immunomodulatory potential.

In neuropod-like models, STC-1 and NCI-H716 cells were used to evaluate vesicle uptake, viability, calcium signaling, and gene expression. Vesicles were efficiently internalized by both cell lines without inducing cytotoxicity. Despite successful uptake, vesicle treatment did not produce strong calcium flux or significant transcriptional changes in genes associated with neuroendocrine signaling. These findings suggest that vesicle interaction alone is not sufficient to drive rapid signaling responses in these models.

Overall, probiotic extracellular vesicles demonstrate clear functional effects in wound healing systems but limited activation in neuropod-like cells under the tested conditions. These results support their potential as modulators of tissue repair and as delivery vehicles for microbial signals, while also highlighting the need for more complex models to study gut-brain communication.