Varun Tadimarri (@varunsays.bsky.social)

Developing an In Vitro Model of Endotoxemia to Assess the Immunomodulatory Effects of Anti-Inflammatory Peptide-Secreting Living Therapeutics Living therapeutics are attractive candidates to tackle the limitations of classically delivered therapeutic peptides, which are often poorly stable and require cost-intensive modifications. Their functional assessment is limited to animal experiments, which increase the complexity to evaluate the dynamic nature of these systems. Therefore, we developed an in vitro model of endotoxemia using macrophages to assess early-stage anti-inflammatory Living therapeutics. We refined the model based on three anti-inflammatory peptides (KCF-18, I6P7, and α-MSH) and identified suitable therapeutic concentrations and treatment durations. We applied the model to Lactiplantibacillus plantarum TF103, a probiotic engineered to secrete these peptides. The model revealed that Living therapeutics enhanced the effects of the peptides, requiring lower amounts of anti-inflammatory effects. This points to potential synergistic effects between peptides and bacteria. The model presented here allows the investigation of dynamic regimes, which could be useful in the development of complex systems such as the ones encountered in Living therapeutics. https://pubs.acs.org/doi/10.1021/acsptsci.5c00216